The Last Fortress: An unforgettable FBI crime thriller

by D.K. Warren

277 pages, Kindle Edition

Published April 22, 2026

Reviews

[Kellyanne · Rating 5 out of 5]

FBI forensic psychologist Dr Ava Locke is deep undercover, infiltrating a sophisticated continental labour trafficking network. Her mission is to dismantle the entire operation and gather evidence against the highest echelons.

When her identity is compromised, she refuses to abort the mission. She uses the chaos to escalate her investigation toward the central command hub.

Ava's success lies in her cold, analytical approach, viewing the complex organisation as a system to be dismantled. Her target is the 'head of the snake,' the untouchable leader. As she closes in, shocking revelations about the leader's identity and motives force a profound personal and ethical reckoning, transforming the takedown into a deeply personal conflict.

I received an ARC through "Booksprout", and I am voluntarily leaving an honest review.

[Roger · Rating 4 out of 5]

The Last Fortress: An unforgettable FBI crime thriller (Dr. Ava Locke Series Book 4), my fifth read from author D.K. Warren, all in the Dr. Ava Locke series, the best book in the series to date. I enjoyed the story-line with more intricately woven twists and turns than the Gordian Knot, I don't think anyone but the author seen this one coming. I couldn't turn the pages of this conspiracy thriller fast enough. I was given a complementary Kindle copy of this book and am voluntarily reading & reviewing it. I look forward to reading more from this author as they're published. (RIP Marley January 20, 2014 - July 24, 2018).

[Debra Tunnicliffe · Rating 5 out of 5]

Another brilliant intense story following Dr Ava Locke as she goes undercover to infiltrate a trafficking pipeline and she arrives at the depot posing as Evie Sterling looking to purchase for workers.

As she goes deep into the operation it becomes more dangerous and she is on her own with no team and must rely on her training to survive.

This is a riveting and fast paced story full of action that keeps you wanting to read more until the end.

Would highly recommend for a action packed story.

I received an advance review copy for free, and I am leaving this review voluntarily

[Terry M · Rating 5 out of 5]

Ava goes under cover to expose labour trafficking. She is discovered, but survives, taking it one step further to take down the hub of it all. Her clinical approach goes far beyond anything else and as she aims to take down the head of the snake, she is faced with unexpected revelations and consequences. I received a complimentary copy and I am leaving this review voluntarily.

[Angee Owens · Rating 5 out of 5]

This is book 4 in the Ava Locke series. Ava is an FBI forensic psychologist and is undercover to infiltrate a labor trafficking network. I love that Ava is a strong, independent character. She doesn’t back down. Even when her mission is compromised, she doesn’t give up. It’s a wonderful story with great characters and an overall great read. 4.5 stars

[Kenneth Lingenfelter · Rating 4 out of 5]

FBI Ava Locke goes undercover to infiltrate a labor trafficking organization that has them sign a binding contract that locks them in. She gets discovered and the action part of the novel kicks in. A page turner.

[Nicole Collins · Rating 5 out of 5]

this was a really good book I enjoyed reading this I have read other books by this author and I look forward to reading more from them they are always so good.

I received a free copy of this book via Booksprout and am voluntarily leaving a review.

[Michael Arnold · Rating 5 out of 5]

Received as ARC. Great story with a unexpected plot twist