Grave Waters

Cassidy Knox #3

by Shannon Hollinger

Most federal agents can go their entire career without encountering a serial killer. For Cassidy Knox, it’s starting to feel like she’s collecting them.

With her retirement from the Bureau looming on the horizon, FBI Special Agent Cassidy Knox is focusing on her new life, one that’s filled with running the animal sanctuary she inherited... and a budding relationship that’s heating up. But when the body of a man is pulled from beneath the murky waters of the Florida Everglades, locked in a giant crab trap, a personal connection to the victim drags her back into the darkness she longs to escape.

Jumping deep into the investigation, what began as a reluctant favor takes a terrifying turn as Cassidy uncovers that the tiny town of Gator Glade has a serial killer on its hands. Still bearing the scars of her last encounter with that kind of evil—one that she barely survived—she’s forced to confront her deepest fears.

As a stalker watches her every move and darkness creeps closer, Cassidy races to untangle the twisted links between the victims. But as she digs deeper, she uncovers a chilling connection—and realizes the hunter is lurking closer to home than she ever imagined. With danger around every corner and eyes following her from the shadows, will she once again find herself in a killer’s grasp?

Dive into Grave Waters for a thrilling blend of mystery, suspense, and romance that will have you turning pages late into the night.

Kindle Edition

Expected publication March 27, 2026

About the author

With degrees in Crime Scene Technology and Physical Anthropology, Florida writer Shannon Hollinger hasn’t just seen the dark side of humanity—she’s been elbow deep inside of it! She’s an avid animal lover, reader, and hiker, and has been known to use her forensic skills to figure out who ate the last cookie in the house.

A multi-genre, Amazon charts top 20 best-selling author, Shannon writes psychological thrillers filled with jaw-dropping twists and shocking endings, the police procedural Chief Maggie Riley mysteries, where the darkness of the Maine wilderness is rivaled only by the deadly secrets it conceals, and the romantic suspense Cassidy Knox mystery thrillers, where the animals will steal your heart and the nights are as hot as the days.

Her novels have been translated into multiple languages, and her short fiction has appeared in Suspense Magazine, Mystery Weekly, and The Saturday Evening Post, among many other magazines and anthologies.

Shannon is a member of the International Thriller Writers and the Short Mystery Fiction Society.

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Reviews

[Carol Nauss · Rating 5 out of 5]

"I don't go looking for trouble but I have a habit of finding it". So true of FBI agent Cassidy Knox. Life is not simple for Cassidy once bodies in crab traps start surfacing. There is a serial killer at large and Cassidy is quickly involved in finding the killer. I love this series and especially the tough, resilient character of Cassidy. The plot is suspenseful and has twists I didn't see coming. Each book in the series builds on the prior book but can be read as a standalone, but do yourself a favor, and read the entire series. You won't be disappointed.

[Dawn · Rating 5 out of 5]

I really love this series! Cassidy and Jake are excellent characters that you just want to keep reading about book after book. Cassidy is called in and reinstated to find a possible serial killer. All roads lead to someone at Jakes job. Does Jake know? Who and why are men being killed? You have to read to find out. I literally read this book on one day. It's SO good !

[Heather Flaherty · Rating 5 out of 5]

I am loving the Cassidy Knox series and this third book is phenomenal! Cassidy’s life is going great for once and things with Jake are incredible. As a favor to a friend, she jumps in to try and figure out why a man was just pulled out of the water. Enter a serial killer. Victims start surfacing in crab traps and someone is stalking her. Can she expose this killer before she is the next victim?

[Maureen ~Bitch Can Write A Book · Rating 5 out of 5]

Welp. She did it again. This may be my favorite one so far. Every book just gets better. Great characters and I literally want to climb in the book and visit this animal sanctuary. I’m looking forward to getting back to this crazy town…Gator Glade. Cassidy Knox is quickly becoming a favorite charter!