Jump to ratings and reviews
Rate this book
Rate this book
Natasha Mayston wasn’t expecting anyone to knock on her door so late at night. And she has no idea that the face staring back at her is the last one she’ll ever see…

As Detective Dan Lockhart is called to a wealthy London street to investigate Natasha’s death, he’s startled by the similarity to a previous case. Noticing the cable-tie restraints and the tiny scratches on Natasha’s wedding finger, Dan already knows what he will find if he looks in her mouth – the metal ball which choked her to death. He knows Natasha isn’t the killer’s first victim and is certain that he will strike again.

Months earlier, Kim Hardy was found in the same position in a run-down hotel across the city – an identical silver ball in her throat. But Kim’s murderer was caught and sent to prison – did they arrest the wrong man? And what connects the two victims? Fearing that he’s dealing with a psychopathic serial killer, Dan calls in psychologist Dr Lexi Green to help him to get into the perpetrator’s mind. Tough and smart, Lexi will stop at nothing to hunt down the man responsible for the deaths.

Then, another body is discovered, just as Lexi finds a clue online leading to the killer. Dan’s team aren’t convinced, but in pushing Lexi away from the investigation, they force her to dig further into the case on her own. Convinced that she’s on to something, she puts herself in unthinkable danger… but can Dan piece together the clues and identify the killer before it’s too late?

Fans of Angela Marsons, Robert Dugoni and Cara Hunter will love this thrilling new series from Chris Merritt. From an explosive start to a heart-stopping finale, you will not want to put this book down!

392 pages, Kindle Edition

First published March 13, 2020

3549 people are currently reading
3712 people want to read

About the author

Chris Merritt

12 books182 followers
Hello! I'm a British author whose crime thrillers combine psychology, suspense, and characters you care about.

All my novels are set in London, where I live. My first trilogy starred Zac Boateng and Kat Jones, two detectives motivated by family, who tackle organised crime and police corruption. LAST WITNESS, the second Boateng and Jones book, reached #13 in the UK Kindle chart in 2019.

My second series features detective Dan Lockhart - an ex-soldier with a missing wife - and psychologist Dr Lexi Green, an American living in London. These novels are darker, more psychological serial-killer cases, with romantic relationships as a central theme.

I began writing fiction in 2014, after previous careers as a diplomat, based in Iraq and Jerusalem, and later as a psychologist working with victims and perpetrators of crime. I specialised in treating Post-Traumatic Stress Disorder (PTSD), which sparked my interest in telling stories about how people cope when faced with extreme adversity.

Now, I spend most of my time writing novels and drinking coffee while 'thinking' about writing novels. When I'm not writing, I love climbing and playing basketball.

Ratings & Reviews

What do you think?
Rate this book

Friends & Following

Create a free account to discover what your friends think of this book!

Community Reviews

5 stars
2,132 (42%)
4 stars
1,916 (37%)
3 stars
778 (15%)
2 stars
180 (3%)
1 star
53 (1%)
Displaying 1 - 29 of 324 reviews
Profile Image for Debra - can't post any comments on site today grrr.
3,269 reviews36.5k followers
March 9, 2020
Lately I have been reading books where doorbells (or knocking on doors) play a key part. Things I have learned from reading those books: DO NOT ANSWER YOU DOOR LATE AT NIGHT. Easy as that folks. That package being delivered, if you don't remember ordering it...THEN YOU DIDN'T...don't open the door. Nothing good can come of it. Whew!

Detective Dan Lockhart is called in to investigate a recent murder of a woman killed in her home. Tied to a chair, scratches on her ring finger and a metal ball jammed down her throat... this murder is very similar to another murder which occurred months earlier. It won’t be the last murder either. What do the victims have in common? Are the murders connected? Why and how were these women picked?

Believing he has a serial killer on his hands, he calls in a psychologist with forensic experience, Dr Lexi Green to provide insight into the mind of the killer. Another piece of advice, if you call someone in for their expert opinion - LISTEN TO THAT OPINION. Seriously, taking advice and not answering the door would have avoided a lot of horrible things.

This is the first book in what is to become the Lockhart and Green book series. The two characters are both interesting. Merritt has me intrigued with both. I look forward to reading more installments in this series and look forward to character development. I also enjoyed the secondary police characters as well. I found this book to be enjoyable, but I did find some sections to be long winded and wanted to skim through them. They slowed the book down a little for me. I had a couple of theories about the identity of the killer and was WRONG. Which was nice because I enjoyed being surprised.

A solid start to a new series and I look forward to reading the next installment.

Thank you to Bookouture and NetGalley who provided me with a copy of this book in exchange for an honest review. All the thoughts and opinions are my own.
Profile Image for PamG.
1,303 reviews1,045 followers
March 2, 2020
KNOCK KNOCK by Chris Merritt is the first book in the Detective Lockhart and Green police procedural series. It is also my first book by this author. Detective Inspector Dan Lockhart is a member of a Major Investigation Team (MIT) in London that focuses on murder investigations. On his person time, he is also seeing a psychologist, Dr. Lexi Green to help him deal with several issues including the disappearance of his wife and PTSD related to his military time. When he gets his first assignment as Senior Investigation Officer, the death seems very similar to a case three months ago. As the deaths mount up, Dan brings in Lexi to consult on the case.

Not only do Dan and Lexi’s characters feel compelling, you understand their distinct flaws and virtues. While both have clear and similar goals, the path there is not the same and provides both internal and external conflicts. Their motivations seem believable. Key secondary characters are also well-rounded and enhanced the story. The plot twists and turns keep the reader guessing and there are plenty of suspects.

The title was intriguing and a meaningful representation to the storyline. The prose was well-written, absorbing, and steadily paced. The plot was engrossing, interesting, well-researched, shocking, and ominous.

Overall, this was a well-written British police procedural. I was immediately drawn into the story and the ending was dramatic. I am looking forward to this author’s next book in this series and I also want to read his Detective Zac Boateng series.

Thanks to Bookouture and Chris Merritt for an ARC of this novel via NetGalley and the opportunity to provide an honest review. Opinions are mine alone and are not biased in any way.
Profile Image for Sandysbookaday (taking a step back for a while).
2,635 reviews2,472 followers
March 25, 2020
EXCERPT: If she'd known it was to be her last night alive, he wondered, how would she have spent it? Gossiping in an over-priced bar with her friends and dancing until the early hours? Or hooking up with one of those square-jawed randoms she seemed to collect on Tinder? Perhaps she'd get sentimental, gathering her relatives privately for a solemn, tearful goodbye. Knowing her though, his guess was hosting an obscenely expensive, self-aggrandising charity bash with champagne and fireworks. She certainly wouldn't have chosen to sit alone like this, tapping away her final hours at a computer.

ABOUT THIS BOOK: Natasha Mayston wasn’t expecting anyone to knock on her door so late at night. And she has no idea that the face staring back at her is the last one she’ll ever see…

As Detective Dan Lockhart is called to a wealthy London street to investigate Natasha’s death, he’s startled by the similarity to a previous case. Noticing the cable-tie restraints and the tiny scratches on Natasha’s wedding finger, Dan already knows what he will find if he looks in her mouth – the metal ball which choked her to death. He knows Natasha isn’t the killer’s first victim and is certain that he will strike again.

Months earlier, Kim Hardy was found in the same position in a run-down hotel across the city – an identical silver ball in her throat. But Kim’s murderer was caught and sent to prison – did they arrest the wrong man? And what connects the two victims? Fearing that he’s dealing with a psychopathic serial killer, Dan calls in psychologist Dr Lexi Green to help him to get into the perpetrator’s mind. Tough and smart, Lexi will stop at nothing to hunt down the man responsible for the deaths.

Then, another body is discovered, just as Lexi finds a clue online leading to the killer. Dan’s team aren’t convinced, but in pushing Lexi away from the investigation, they force her to dig further into the case on her own. Convinced that she’s on to something, she puts herself in unthinkable danger… but can Dan piece together the clues and identify the killer before it’s too late?

MY THOUGHTS: I started this book with great excitement. I love this author's Zac Boateng series, and I was looking forward to more of the same. WRONG. Knock Knock is very different. Where I found the Zac Boateng series to be fast paced, suspenseful and thrilling, Knock Knock seems to be drawn out and, to be quite honest, I found myself skimming passages where the author seemed to be pontificating/procrastinating. Don't get me wrong - this is not a bad read, and I will give this series a second chance, but it needs to be tightened up, to be not quite so bogged down in repetitive psychological analysis.

I liked the characters: Dan, Detective Lockhart whose wife has disappeared without trace; Maxine Smith, a strong character inclined to follow her instincts; Lexi Green, psychologist, who also has trauma in her past. Even the lesser characters, the supporting cast, are an interesting bunch. The chapters written from the POV of the murderer were mostly interesting, but a little repetitive.

The basic plot is sound, and there are a few interesting twists and misdirections. I did have fun trying to guess the killer - I didn't even come close.

I hope this does develop into a good series. I know Merritt has the talent.

Love the cover. *:)

👮‍♂️🎭🚔

#KnockKnock #Netgalley

THE AUTHOR: Hello! I'm a British author whose crime thrillers combine psychology, suspense, and characters you care about.

All my novels are set in London, where I live. My first trilogy starred Zac Boateng and Kat Jones, two detectives motivated by family, who tackle organised crime and police corruption. LAST WITNESS, the second Boateng and Jones book, reached #13 in the UK Kindle chart in 2019.

My second series features detective Dan Lockhart - an ex-soldier with a missing wife - and psychologist Dr Lexi Green, an American living in London. These novels are darker, more psychological serial-killer cases, with romantic relationships as a central theme.

I began writing fiction in 2014, after previous careers as a diplomat, based in Iraq and Jerusalem, and later as a psychologist working with victims and perpetrators of crime. I specialised in treating Post-Traumatic Stress Disorder (PTSD), which sparked my interest in telling stories about how people cope when faced with extreme adversity.

Now, I spend most of my time writing novels and drinking coffee while 'thinking' about writing novels. When I'm not writing, I love climbing and playing basketball.

DISCLOSURE: Thank you to Bookouture via NetGalley for providing a digital ARC of Knock Knock by Chris Merritt for review. All opinions expressed in this review are entirely my own personal opinions.

For an explanation of my rating system, please refer to my Goodreads.com profile page or the about page on sandysbookaday.wordpress.com

This review and others are also published on Twitter, Amazon and my webpage https://sandysbookaday.wordpress.com/...
Profile Image for Sarah.
2,956 reviews223 followers
February 15, 2020
Being a huge fan of the authors Detective Zac Boateng crime series, I was very excited to see that not only did he have a new novel coming out but it was the first in another crime series. This time featuring Detective Dan Lockhart and psychologist Dr Lexi Green.

Dan comes across as being a genuinely nice guy. His personal life isn’t without issues though, of which I am very keen to learn more about. Same goes for Lexi. I loved her strength and her role ties in very nicely with Dan and the case he soon starts working on.

The killer in the book is sadistic and how they murder their victims, well let’s just say my hand was pretty much resting on my throat at the thought it all. I am praying I don’t have nightmares after reading it!

The majority of the story focuses on Dan and Lexi rather than the killer. I have to say with how horrible the killer is, I am actually quite grateful for this. It sets the new series up well, getting a real feel for the two main characters of which has left me excited for more.

Knock Knock is a spine chilling read that had me squirming in my seat more than a few times. It is steadily paced with a turbo injection that sent me hurtling towards the end to see how it was all going to pan out. I think I may have actually forgot to breath at some points and even hours after finishing it, my heart was still racing. An adrenaline, page turner of a read.
Profile Image for Xavier Hugonet.
177 reviews14 followers
February 13, 2020
Knock Knock is the first book in a new series by author Chris Merritt, featuring DI Lockhart and Green. It’s a British police procedural.

At 416 pages, it’s longer than usual crime series books. The extra page count is used by the author to fully develop an ensemble cast of compelling characters. The story may be subtitled Lockhart and Green but, written in the third person, it switches between the narrative of each member of the investigative team.

DI Lockhart is a mid thirties DI in London Putney’s Major Investigation Team. A veteran, he’s seeing a therapist, not about PTSD from the war (although he’s not immune), but about the mysterious disappearance of his wife while he was deployed ten years prior. The series title is misleading, as we could assume Green is also a detective. She is not. Lexi Green is the therapist, and Lockhart is going to bring her to consult on his first case as SIO. A possible serial offender.

This serial killer is an extremist from a fringe group those roaming social media unfortunately know all to well, the incels. Fueled by his hate towards women, and galvanized, radicalized even, by an academic « guru » and his despicable peers on the Internet, he’s killing to fight his self loathing, and make a statement.

For those fortunate enough to not know anything about incels, learning (as the author states in his afterword), than everything about it in the novel is true will probably be quite a shock.

The killer is particularly cautious, and the investigation is difficult, going nowhere for quite a while. Several characters, such as Lockhart, Green, DS Smith and her partner Khan actually follow different lines of investigation, and sometimes even openly disagree about steps taken. All those characters have qualities and faults, and the narrative exploring and following each of them is remindful of Ed McBain’s works.

The author has done his research about the world he brings us in, and the police procedural aspects also feel quite authentic, making Knock Knock a thriller difficult to put down.

By the end of the book, we’ve learned to know and appreciate each member of Putney’s MIT, including the obligatory grumpy and political DCI, and it’ll be a pleasure to join them on another investigation (already planned to be released summer 2020).

Thanks to Netgalley and Bookouture for the ARC in exchange for this unbiased review.
Profile Image for Rose.
305 reviews142 followers
February 26, 2020
Thank you to NetGalley, Bookouture. And Author Chris Merritt for my advanced copy of Knock Knock, in exchange for an honest review

Knock Knock by Author Chris Merritt is the first book in a new series featuring Detective Dan Lockhart

This was a great read, and the series is off to a very good start. I will look forward to see where the author takes this series, and characters.

The storyline takes place in London, with what appears to be a serial killer on the loose. The detective asks for the involvement of a psychologist Dr Lexi Green

Non stop action, and a very enjoyable thriller

A book I would recommend, for readers who enjoy Thrillers, and Mystery books.
Profile Image for 8stitches 9lives.
2,853 reviews1,724 followers
March 14, 2020
Knock Knock is the first instalment in Mr Merritt’s exciting new series featuring Detective Inspector Dan Lockhart, an ex-soldier with a missing wife and working as part of the Major Investigation Team (MIT) in Putney, and Doctor Lexi Green, an American psychologist living in London. Dan is called in to investigate when wealthy and successful Natasha Mayston is found tied up in her own home with a metallic ball thrust down her throat to choke her to death; she would’ve suffered an excruciating demise as she gasped for air. Dan believes she is the victim of a brutal serial killer who offed sex worker Kim Hardy a mere few months ago yet another man has been charged with her killing. Another mechanical suffocation, a sinister and unique modus operandi, takes place a few weeks after Natasha’s murder and then another body drops. Dan invites Lexi to help out with the case much to his team’s dissatisfaction as they need to identify and apprehend this twisted, disturbed killer before he strikes again.

This is a tense, exciting and superbly crafted police procedural and at over 400 pages it is admittedly slightly longer than usual but Merritt uses the extra pages to introduce and develop his characters far better than most other books in the genre. I loved the deliciously depraved and original MO of the serial killer and it made for refreshing reading. Also, the use of a psychologist to create a likely profile of the killer reminded me of shows like Criminal Minds and was nothing less than fascinating. There are some shocking twists in this dark tale and using such a topical issue, the incel community, as the reason for murder was inspired. Incels, or involuntary celibate, have been all over the news of late with their hatred of women and misogynistic views and that is what really drives this whole story. There is a decent amount of possible suspects and the author manages to keep you guessing, wrongly might I add, right until the heart-pounding and riveting conclusion. Many thanks to Bookouture for an ARC.
Profile Image for Nila (digitalcreativepages).
2,667 reviews222 followers
February 16, 2020
Move over, the book boyfriends of Bookouture. Dan Lockhart is here!! The new heartthrob... Or should I say Chris Merritt is here!! Well, it is my first Chris book.

A woman found dead with a metal ball deep in her mouth, choking her. Slow excruciating death. DI Dan Lockhart was called in along with his team. And he pulled in his psychologist and forensic expert Dr. Lexi Green.

At 416 pages, the book was a wee bit long and detailed. Or maybe I just wanted to get to the killer faster. The author's writing was fascinating as I got to know both sides of the spectrum. The cops and the killer, especially the Guru of the killer who thought men were superior. I was ready to karate chop that man, only the fact that my kindle would pay the price stopped me. Oh yeah, my blood boiled while reading the killer sections. He was completely revolting, and I loved to hate him.

Dan and his team had a newness to them, they got comfortable with each other slowly down the pages. There were skirmishes, some went in different directions. I liked how the author kept the prose authentic as it did take a team time (or a book) to become cohesive.

Dan found his footing slowly, the latter half had me turning the pages faster to get to the killer. I played the Detective but lost to the author, as the identity was a shocker. But then I blame my illness. I will do better in the next book.

Overall, a gripping read which kept my brain occupied for a few hours. I would love to see what Dan and his author Chris bring to the next book
Profile Image for Kat (Katlovesbooks) Dietrich.
1,531 reviews202 followers
March 16, 2020

Knock Knock by Chris Merritt
is the first in the new Detectives Lockhart & Green series.

First, let me thank NetGalley, the publisher Bookouture, and of course the author, for providing me with a copy of this book in exchange for an honest review. All opinions are my own.

 
Series Background:   

DI Dan Lockhart is a detective in the Major Investigation Team (the Murder Squad).  He is still trying to come to terms with his wife's disappearance 10 years ago.  He has been seeing Psychologist Dr. Lexi Green, who is still trying to get over the loss of her brother.



My Synopsis:   (No major reveals, but if concerned, skip to My Opinions)

When the dead body of a woman is found in her home, Dan is called in, and for the first time, made Senior Investigative Officer (SIO) of the case.  One look at the body, and Dan is sure that this is not the first kill by this perpetrator.  He is sure that he has a serial killer on his hands.  The cable ties, the injury to the ring finger, the metal ball in the victim's throat....he's seen it before.  His boss disagrees.  Now Dan just has to link this rather wealthy woman to the sex worker who was tortured in an identical manner.  Dan calls in Lexi to see if she can help.

When Lexi's profile is dismissed by both Dan and his colleagues as being psychobabble, she only digs in her heels, especially when another woman's body is found.  Determined to prove her point, Lexi creates a fake "man" to access the websites where she is sure the killer is lurking.  She puts herself in terrible danger.

 

My Opinions:  

This was a great start to a new series.  This is the first book I have read by this author, but I found his writing to be very clear, and concise.   Even though the book is fairly long, it was a fast read, mostly due to the non-stop action.  Things moved along very well.

I love the fact that both main characters are trying to come to terms with a loss.  Both Lexi and Dan are strong characters, and both are likable.  Their relationship is building slowly, as they learn to trust each other.  The dynamic is good.

The books main theme is misogyny....an ingrained hatred of women.  The author tried to explain different reasons for this, but I'm not sure he was successful (could be just my female perspective shining through here).  It looks like he did a lot of research into these chat-rooms, etc, and that just scares me....

The plot was well-developed, and there were plenty of suspects to go around, which is a little scary when you think of the theme.

Anyway, I definitely enjoyed the direction this new series is headed, and I'm looking forward to more! 


For a more complete review of this book and others (including author information and quotations), please visit my blog: http://katlovesbooksblog.wordpress.com/
Profile Image for Adrian Dooley.
507 reviews159 followers
March 25, 2020
The first in a new series called Lockhart and Green, I thought it may have been more appropriate being called Lockhart with a side of Green or even Lockhart and Smith!

Detective Dan Lockhart is our main character here. Ex army, wife missing presumed dead by all except himself and his mother. Dr Lexi Green is his psychologist. He is seeing her before work on his own time.
When he investigates a couple of gruesome murders of women with the exact same methodology, he is one of the first convinced they have a serial killer on their hands even though the women have nothing in common at all.
He calls in Dr Green to try and help profile the killer(even though she has not experience or expertise in this field!)

This one for me is just ok. Interesting enough premise but a few bits to annoy to stop it scoring higher. Firstly Greens decision to act as a consultant on one of her clients cases just seemed a bit of an unrealistic scenario. She also makes some pretty stupid decisions, especially towards the end of the book which seemed totally illogical. Their whole sexual chemistry thing also felt quite clumsy and a excuse to throw them together in a professional capacity which just didn’t seem realistic at all.

Also this is titled as a Lockhart and Green book but to be honest it isn’t. It’s a Lockhart book. Green is very much a secondary character, one of numerous in the book. Lockharts female colleague Smith features at least as much if not more than Green.

While the premise for the story is sound, the book does feel overlong for what it is. It dragged a bit for me and felt a lot longer than it needed to be. Too much padding and pontificating for me to hold a real interest or build any real tension.

It’s not a bad book per say but too many irritants for me to enjoy to any great degree.

Many thanks to Netgalley, Bookouture and Chris Merritt for an ARC in exchange for an honest review.
Profile Image for Linda Strong.
3,878 reviews1,708 followers
September 13, 2021
Detective Dan Lockhart is called to investigate when a woman is found murdered in her home. He's surprised to see that the scene is similar to another murder that took place months ago. But that murderer was caught and sent to prison.

Lockhart wonders if they put an innocent man away. And what connects the two victims? Fearing he has a psychopathic serial killer on his hands, he calls in Dr. Lexi Green to help put a profile together. Tough and smart, Lexi will stop at nothing to hunt down the man responsible for the deaths.

Then a third body is discovered. Lexi has found a clue that she feels will lead to the killer, but Dan's team isn't too sure. Fearing that they are pushing her away from the investigation, she puts herself out there as bait.

This is the suspenseful beginning of a crime fiction series. I love getting in on the ground floor of a new series, reading the characters backstories, finding those little gems that make a good series even better.

The characters are finely drawn, fully fleshed out, and their investigation is realistic, police procedural is credible. This is an action filled page turner with twists and turns that lead to a most unexpected conclusion.

Many thanks to the author / Bookouture / Netgalley for the digital copy of this crime fiction. Read and reviewed voluntarily, opinions expressed here are unbiased and entirely my own.
Profile Image for Samantha.
418 reviews43 followers
May 6, 2020
A brilliant new series with a fine team leading the way! Whenever I pick up a new book belonging to series, I am very eager to see if the lead detective/team makes it to my list of favorites. I'd like to think I have set my standards very high with the likes of Kim Stone, Erika Foster, Callanach, and the likes. I do not want to compare this book to any of those other series because this one is so unique. But I also want to say that this book is definitely in league with the others I hold such high admiration for. This series with just its first installment was such a compelling read. Knock Knock did not just make it to my favorites' list, it also left me with a bad case of needing to read the next book in the series asap! Detective Lockhart & Green are a dynamic duo hunting down an unhinged killer killing innocent women leaving behind a gruesome signature. I loved this book for all it is - Its a gripping page-turner for sure!

Detective Dan Lockhart is called to the scene of a grisly murder. Natasha Mayston lies dead in her own home restrained, strangulated & with scratches to her ring finger. Taking in the scene before him, Dan already knows what forensics will find inside Natasha's mouth. Months earlier, one of Dan's informants Kim Hardy a local prostitute was found dead in the same way as Natasha. With Kim's killer already in jail, Dan wonders if the police got the right man? Soon another woman is found dead, restrained, choked & bruises to her ring finger. Fearing of dealing with a serial killer, Dan brings in his psychologist Dr. Lexi Green to help get inside the mind of the killer & narrow down suspects. Eager to help Dan, Lexi works hard at developing a profile for the killer. However, Dan's team is unconvinced about Lexi & her skills leading Lexi to research on her own time pushing her into the crazy killer's crosshairs. Can Dan piece together the clues and identify the killer before it’s too late?

I absolutely loved all the characters in this book. Dan with his past & missing wife makes for a very interesting read. I hope Chris Merritt addresses this mystery in the sequels to this book. Each & every one of Dan's officers' characters was also written in a very descriptive way. The end of the book seriously left me hoping the next book is out soon!! There is so much more to know & I love how this book turned out to be. Knock knock has set the bar very high for the subsequent books in this series & I hope to read all of them (soon).

Thank you NetGalley, Bookouture & Chris Merritt for an arc!
Profile Image for Jannelies (living between hope and fear).
1,308 reviews193 followers
August 12, 2024
In search of something to test the Kindle settings on my new tablet, I found this title. I'm happy to have found it because it is exactly what I like: a good story, likable main characters; a police procedural with thriller and mystery elements thrown in.

By now there are already so many reviews here that I don't think I can add a lot. Suffice to say that this book reminded me of the Craig Gillard series by Nick Louth (which I enjoyed) and of course there is the mystery around the disappearance of Lockharts wife, which sounds familiar because Peter James made it a rather famous theme in his books.

Very well done - I think this won't be the last book in the series that I will read.

Profile Image for Monnie.
1,628 reviews789 followers
February 24, 2020
This is the first in a series featuring London Detective Inspector Dan Lockhart and psychologist Dr. Lexi Green, and while I enjoyed it (the serial killer's modus operandi is unique and wonderfully gruesome), I have to say I never felt a real "connection" between the lead characters. Of course, they're just getting started - and both have baggage from their past lives that weigh down the chances for successful relationships with anyone else. And near the end they both showed a little more emotion, so I do think there's hope for a solid friendship if not romance in future editions.

The two actually met when Dan, whose wife disappeared but so far hasn't been found, began counseling sessions with Lexi. Not knowing whether she's alive or dead has turned Dan into an alcoholic druggie of sorts, although he's able to slog through work when needed. But then, he's called to investigate the murder of a wealthy woman, and the similarities to an earlier murder are almost identical: choked by a metal ball, both women's ring fingers were oddly scratched. Not everyone on Dan's team, including his boss, are convinced that a serial killer is at work, so Dan decides to ask Lexi for professional input as to an overall profile and motive.

Lexi goes to work, coming up with a theory that's linked to an online community of women-hating men. At first, she's paid; but when no one, including Dan, take her work seriously, she decides to show them the error of their thoughts by continuing her work on her own because she's convinced the killer is lurking in the shadows of the Internet "mansphere." Even if neither she nor Dan foresee any danger in that going off the deep end approach (as professionals, it's a mystery to me why neither of them did), readers can see right away where the story is headed.

Meantime, interspersed with the investigation are glimpses into the killer's mind - and the awareness of from whence his inspiration comes. The action leans toward frenetic near the end, which brings a near end to at least one character (nope, not gonna tell). All told, it's a solid start to a new series. I thank the publisher, via NetGalley, for providing me with a pre-publication copy for review.
Profile Image for Julie Lacey.
2,032 reviews129 followers
March 17, 2020
A great start to a new series.
Detective Dan Lockhart is called to a house where a woman has been murdered in a particularly gruesome manner.
Soon more women are murdered so he calls on Dr Lexi Green to give her view on the killer.
Dan and Lexi work together with the team to try and understand what links the women but struggle to find the link.
I really liked Dan and can see this being a great series as we’ve learnt about his past and there’s definitely more to come about this.
I hope Lexi is in the next book too as her relationship with Dan has potential.
This is a gripping crime thriller that I’ve no hesitation in recommending.
Thanks to Bookouture and NetGalley for the opportunity to read this book.
Profile Image for Bridget.
2,789 reviews131 followers
March 21, 2020
It's night-time and Natasha Mayston isn't expecting visitors. Certainly not the man staring at her from across the street, through her porthole window.

As Detective Dan Lockhart is called to a wealthy street to investigate Natasha’s death, he’s startled by the similarity to a previous case. DI Dan Lockhart is an ex-soldier with a missing wife and is currently working as part of the Major Investigation Team (MIT) in Putney, London. Dan believes Natasha is the victim of a brutal serial killer who bumped off sex worker Kim Hardy in a hotel a few months ago, although another man was charged with her killing and is in prison. Dan calls upon psychologist Dr Lexi Green, an American living in London, to assist, alarmed that he’s dealing with a psychopathic serial killer. Just as Lexi thinks she's got a lead on the killer, yet another body is discovered. But Dan’s team aren’t convinced, and in pushing Lexi away from the investigation, she is forced to probe further into the case alone, putting herself in unthinkable danger… but will Dan be able to identify the killer before time runs out for her?

Knock Knock, the first instalment in Chris Merritt’s exciting new series, is a tense, exciting and superbly crafted police procedural. At 400+ pages, the novel is slightly longer than my usual reads, but Chris Merritt uses the extra words to introduce and develop his characters really well. I really like the delightfully depraved modus operandi of the serial killer and it made for compelling and refreshing reading. The use of a psychologist to create a probable profile of the killer is captivating and there are some shocking twists in this dark tale. With a good number of possible suspects, the author manages to keep me guessing right up to the riveting conclusion. A remarkably good story that I can confidently recommend!

I received a complimentary copy of this novel from Bookouture via NetGalley at my request, and this review is my own unbiased opinion.
Profile Image for Andrea Pole.
818 reviews143 followers
March 29, 2020
Knock Knock by Chris Merritt is the first novel that I've read from this author, and a promising introduction to a new series focused on DI Dan Lockhart and psychologist Lexi Green. This is a compelling police procedural but, I must admit, it was a little slow to pull me in. Once it did, though, I was hooked for the duration. Partly told from the chilling perspective of the killer, I had goosebumps each time a potential victim received the dreaded knock on the door. While I did enjoy the development of the characters and the story arc as a whole, I am on the fence about whether or not this will become a series that I will pursue going forward.

Many thanks to NetGalley and Bookouture for the opportunity to read this ARC.
3,216 reviews68 followers
February 17, 2020
I would like to thank Netgalley and Bookouture for an advance copy of Knock, Knock, the first novel in a projected series to feature DI Dan Lockhart of the Putney MITand psychologist Dr Lexi Green.

When Natasha Mayston is found dead in her home, cabled tied to a chair and a silver ball in her throat Dan is sure it is the same man who killed prostitute Kim Hardy a few months previously. Nobody else thinks so as another man has been charged with Kim’s murder so he asks Lexi for help.

I enjoyed Knock, Knock which is a well constructed procedural with several good twists. It is told from various points of view, notably Dan, Lexi and the unnamed killer. This latter is an Incel (involuntary celibate) which is apparently a thing nowadays with several chat forums devoted to their misogyny. Needless to say the celibacy is all to do with women and nothing to do with their characters, as the killer explains frequently. To be frank the (over)dwelling on this hateful point of view put me off the novel a bit. TMI.

Otherwise the plot is well done with several suspects, all with viable motives and opportunities. I would never have guessed his identity. The novel, however, is quite long and the middle mostly consists of the detectives chasing their tails. It does not paint them in a very good light as they appear disorganised and half cocked much of the time. The finale is high octane, tense and exciting.

I liked the friction between Lexi, who is on the right track, and Dan, who dismisses her theories. I’m not sure it’s wholly believable that a struggling investigation wouldn’t at least look at what she has to say but it makes for good reading.

Knock, Knock is a good read that I have no hesitation in recommending.
Profile Image for ☼♎ Carmen the Bootyshaker Temptress ☼♎.
1,753 reviews165 followers
September 7, 2021
Now this was a twisted, crazy, can't put down, story. I wasn't sure where it was going to go or who. There was some crazy moments and people but to find the truth and the "not labeing it as serial killer", lol, was a determination that Det. Lockhart and his team, including Dr. Green weren't giving up. Even though you tend to find some things strange and weird it was a good story and start to this series which I'll continue to see how the team continues through the series. Oh and if you read this book you'll know why I placed quotations on not serial killer. Hahaha
Profile Image for Michelle.
1,754 reviews160 followers
February 21, 2020
Knock Knock is a very good first book in Detective Lockhart and Dr Green series. Chris Merritt is a new author for me, so I was excited to see how this pans out.
Detective Lockhart has experienced a lot so far in his life. He used to be a Military man and now a Police officer. So, you have thought he would be used to see dead bodies. But when he has been called to a murder of Natasha Mayston. The victim being tied to a chair and gagged with a metal ball in her mouth. He wonders if the police have caught the wrong man as a body was discovered months ago and the person was caught and is awaiting trial.
Dan Lockhart also suffers from PTSD after being in the military, so he visits psychologist Dr Lexi Green beknown to the police force. But will her expertise Dan think that Dr Green will be a big help to find out how the killer thinks, what is behind his killings and to find out who the real killer is. So, he asks her for help with the investigation. In his spare time, he keeps looking for his wife that has disappeared years previously.
Knock Knock is excellent start in a new thriller/police procedural. This has everything you want in it, it’s fast paced, addictive, likable characters, especially Lockhart. Maybe I am a little picky, but I found it just a little bit too long. But that didn’t spoil it because I will look forward to the next instalment.

Profile Image for LJ (ljwritesandreviews).
876 reviews41 followers
October 6, 2020
I’ve read a couple of Chris Merritt’s Zac Boateng series, so I was intrigued to see what these new characters, Detective Dan Lockhart and Dr Lexi Green, were like.

Knock Knock is a tension packed serial killer thriller and a great introduction to these new characters.

Dan is a former soldier suffering from mental health issues after his wife disappeared years earlier. Lexi is a talented psychiatrist who can hold her own in most situations. I sensed a bit of romantic tension between the two but having read Chris Merritt’s previous books he never makes anything easy for his characters!

I really enjoyed the secondary cast of characters from Dan’s team, particularly Max, who’s not only a woman trying to make it in a male dominated profession but she’s also missing two fingers and a thumb on one of her hands.

The serial killer in this novel was one of the most despicable I’ve come across, choking women with a metal ball. Yes, all serial killers are awful but this one’s hatred of women and all their accomplishments really dripped from the pages.

I did get a little frustrated with Dan and his team, I mean they brought Lexi in and then pretty much ignored what she said. I hope in the future novels this changes!

This was a solid start to the series with plenty of room for characters to grow. I’m looking forward to reading the second instalment Who’s Next?
Profile Image for Sheila Moore.
75 reviews
February 10, 2020
This book is the first of Detective Dan Lockhart and Lexi Green series (I hope there are more). The story had me hooked from the first chapter. It begins with the murderer standing outside a wealthy woman’s house intent on killing her. DI Dan Lockhart is in therapy with Lexi Green following his PTSD after serving in the armed forces and his missing wife. Lockhart is soon assigned as SIO in charge of the murder assisted by his colleagues Max Smith and Mo Khan. A further murder takes place a couple of weeks later and Lockhart believes there is a serial killer on the loose in London. The 2 murdered woman are both well educated and successful in their respective fields. However a prostitute was killed sometime earlier and one of her clients is held on remand for her murder investigated by a different force in London.. Lockhart believes her murder is connected to the other two, they were all killed in the same way, by mechanical suffocation. Lockhart calls on Lexi Green to carry out a psychological profile but she is not taken seriously by Lockhart’s team members. Lockhart goes against authority to gain access to the man held on reman for the prostitutes murder in an attempt to crack the case. There is a serial killer with a twisted mind still on the loose and he goes on to kill yet again. It is a race against time to catch him before another woman is murdered in this horrific way. The plot is pacy, cleverly written and kept me guessing until the end a rare quality in a talented author who is so obviously well versed in police procedures. The book is tense, the characters well developed and I eagerly look forward to reading the next book in this series. My thanks to NetGalley, Bookoutre and Chris Merritt for this ARC
Profile Image for Neon.
593 reviews13 followers
November 1, 2021
I was bored. Not impressed by characters. I wasn’t surprised by the “suspense”. Cop acts like a rookie and not like a captain or guv or whatever. The psychiatrist was juvenile. She acts like teenager more than a doctor, I pretty much didn’t like anything about this book. How is that it got so many raving reviews?? Yeah, people are changing and so am I.

I finished this book just for the sake of it.
Profile Image for Leah.
170 reviews42 followers
September 8, 2024
3.5 ⭐️

I felt the book rambled on more than it needed to. I did enjoy the constant back and forth thoughts of who the killer could be but so many pages were really redundant.

Profile Image for Dawn.
1,098 reviews19 followers
February 20, 2020
Dan Lockhart has one of the most important cases of his career when a young woman is murdered. His MIT team are at a loss and using his the personal doctor , Lexi Green, To help profile the murderer, she makes headway into the psychology of a killer. Soon more women are being murdered and his team face a frantic fight to save a woman.

This has the bones to be a great series. The characters are very likeable with their own back stories but I just found it a bit slow to start. By the end I was racing through it.

Thank you to netgalley and the publishers for this arc in exchange for my honest review.
Profile Image for Elisabeth Soane.
492 reviews2 followers
February 27, 2020
This is the first in a new series starring Detective Lockhart and Dr Green. General premise is there is a serial killer who is getting access to properties before killing the female tenant. Detective Lockhart calls in clinical psychologist to help with a profile.
I struggled with this particularly when a subplot is that Lockhart’s wife has been missing for several years. Unfortunately this immediately made me draw comparisons with the Roy Grace novels who also had a missing wife. I guessed who the killer was and a further twist to the story.
I read a lot of crime novels and just couldn’t get into this as the main character has been done before and better. There were also issues with the building relationship between Lockhart and Green which goes against the boundaries of therapy as she starts as his therapist.
I think I’d you don’t ordinarily read this genre you may find it enjoyable but I did not.
Thanks to Bookouture and NetGalley for an ARC in exchange for an honest review.
#KnockKnock #NetGalley
Profile Image for Robyn.
424 reviews104 followers
March 18, 2020
Knock Knock is the first book in the Detectives Lockhart and Green series by Chris Merritt. Merrit is a new to me author and I must say I am now certainly a fan! This is another serial killer story I am adding to my collection.

While investigating a new murder scene, Detective Inspecter, Dan Lockhart, is shocked to see similarities to that of another previous murder, but the offender was already caught and awaiting trial. Has the wrong man been arrested and is there a serial killer running loose killing women? Dan brings in Psychologist Lexi green, hoping she can give some insight to the killer before he strikes again. But, as Lexi digs deeper into the murders she finds herself directly in the crosshairs of a killer.

I must admit the title of this book really gave me goosebumps because I always have this fear that late at night someone is going to knock on my window or my door and scare the living daylights out of me. Hey, it can happen! So, when women are starting to be killed after answering a knock at their door, I found myself listening to every freakin sound in my apartment. Talk about a total meltdown every time my cats made a huge noise or a bang while reading this story had me practically jumping out of my chair. I am such a wuss!

I really loved Dan Lockhart and how determined he was to catch a killer while dealing with his own personal issues and family life. Nothing stood in his way and he went through all the evidence stacking up with a fine tooth comb trying to prevent another murder. He brings in Lexi Green as a forensic consultant to deliver a profile on the killer. But when her offer of help and profile on the killer goes unnoticed by the detectives working the case, Lexi takes matters into her own hands to find the person responsible. I liked Lexi, but found her to be a bit naive as well as making a few rookie mistakes in her quest to catch a killer. I do love the dynamic between Dan and Lexi though and I think they make quite a team, if only Dan takes her more seriously next time.

This is a pretty long book at over 400 pages, but I found the story to be moving and never really lagged in the action. There are many twists and turns as well as quite a few people I liked for the killer. Although I did try my best, I never really figured out who it was until the big reveal. I was pretty immersed in this story throughout and found I was unable to put the book down, which meant I had a long night ahead of me reading. I should know better by now NOT to start reading a book after 11PM!

Knock Knock is a gripping crime thriller and will certainly make you think twice when you hear a knock on your door late at night! This is a great start to a new series and one I am certainly going to be following. Oh man, that ending too, what a way to keep me invested in anticipating the next book!

Profile Image for Hannah stressedreader .
278 reviews29 followers
February 27, 2020
4.5 - 5

Wow! This is one of best books I have read so far this year. Really incredible! I was hooked from the get go. The method in which this man killed people was horrifying. I loved the characters. It reminded me a little of Cara Hunter's series as its told by different investigating officers throughout. I knocked some points off as at the end I thought I guessed who the bad guy was and I was so shocked and impressed.. and then it turned out not to be them! If you love crime thrillers following the police investigating the crime then add this to your wishlist now. I can't wait for the second installment.

Thank you to netgalley for a copy of this book in exchange for a review!
Displaying 1 - 29 of 324 reviews

Can't find what you're looking for?

Get help and learn more about the design.