At seven years old, the girl known only as "Zero" was locked away in an Idaho dungeon. Her torments didn't end for nine years, until she broke free and executed her captors. But her vengeance couldn't end there. When Zero was locked away, she had a little sister, Hope. She never saw her again, but she's been searching ever since. Now she may finally be getting close.

FBI Special Agent Katie Winter is no stranger to frigid winters, isolation, and dangerous cases. With her sterling record of hunting down serial killers, she is a fast-rising star in the BAU, and when a woman is discovered in the middle of a frozen lake, Katie is the natural choice to partner with Canadian law enforcement to track the killer across the brutal and unforgiving landscape.

Alexa Chase, 34, a brilliant profiler in the FBI’s Behavioral Analysis Unit, was too good at her job. Haunted by all the serial killers she caught, she left a stunning career behind to join the US Marshals. As a Deputy Marshal, Alexa—fit, and as tough as she is brilliant—could immerse herself in a simple career of hunting down fugitives and bringing them to justice.

In No Mercy (Book 1), when a serial killer escapes from a mental hospital, the FBI creates an elite unit to target criminally-insane killers. FBI Special Agent Valerie Law, a rising star, is the perfect candidate—but for Valerie, this case may just hit too close to home. With an insane killer on a spree, the clock is ticking for Valerie and her partner—and the brilliant psychiatrist on their team—to enter his mind and stop him before he strikes again.

FBI Special Agent Eve Hope can’t escape the shadow of her notorious serial killer father—though he is jailed, the puzzle of the loving father of her childhood haunts her, and now, assigned to a copycat case, she is forced to face her worst memories. Can she stop this new killer before he claims a new victim—while saving herself from being swallowed by her past?

A serial killer following the seven signs of the Messiah. An ex-con FBI agent seeking redemption. A riddle that must be cracked as a victim’s precious time runs out....

FBI Special Agent Taylor Sage has crossed the country and transferred to her dream job with the BAU at Quantico. With a new job, a new house, and her husband by her side, Taylor is ready to put the darkness of her past behind her: a sister who vanished when she was a teenager.

Beth and Tom Hardcastle are the envy of their neighbourhood—they have the perfect marriage, the perfect house, the perfect family. When the police knock on their door one evening, Beth panics. Tom should be back from work by now—what if he’s crashed his car? She fears the worst. But the worst is beyond imagining. As the interrogation begins, Beth will find herself questioning everything she believed about her husband.

The names of notorious serial killers are usually well-known; they echo in the news and in public consciousness. But most people have never heard of Israel Keyes, one of the most ambitious and terrifying serial killers in modern history American Predator is the ambitious culmination of years of interviews with key figures in law enforcement and in Keyes's life, and research uncovered from classified FBI files. Callahan takes us on a journey into the chilling, nightmarish mind of a relentless killer, and to the limitations of traditional law enforcement.

When the body of a woman is found hanging from a tree in her front garden, rookie Detective Morgan Brookes is first on the scene. But Olivia Potter is past saving. And when her husband and daughters cannot be traced, Morgan knows there is more to this tragedy. And then she finds them. Lying huddled together in the dark basement, each of their faces covered with a small cotton cloth, their bodies cold to the touch. But as Morgan kneels beside the family, she realizes that one of the girls is still breathing.

A cop lies dying beneath the blistering Arizona sun - a local lawman who may well have become the next sheriff of Cochise County. The police brass claim that Andy Brady was dirty, and that his shooting was a suicide attempt. Joanna Brady, his devoted wife and mother of their nine-year-old daughter, knows a cover-up when she hears one...and murder when she sees it.

When her 13-year-old sister vanishes on her way back from a friend’s house, Detective Kaitlyn Carr must confront demons from her own past in order to bring her sister home. The small mountain town of Big Bear Lake is only three hours away—but a world away from Kaitlyn's life in Los Angeles. It’s the place she grew up and the place that’s plagued her with lies, death, and secrets. As Kaitlyn digs deeper into the murder that she is investigating and her sister's disappearance, she finds out that appearances are misleading, and few things are what they seem.

A lifeless girl slips into the river, cold and crumpled. Her body washes away with the rain. Her killer remains a mystery. Sheriff Elven Hallie has been longing for a new case that would add some excitement to his small-town life. But a dead girl wasn’t what he expected. On the last murder case he worked, he was just a deputy with an experienced Sheriff to guide him and they were looking for an outsider. This time, he’s in charge, and the killer is part of their community.

FBI Special Agent Maya Gray, 39, has seen it all. She’s one of BAU’s rising stars and the go-to agent for hard-to-crack serial cases. When she receives a handwritten postcard promising to release 12 kidnapped women if she will solve 12 cold cases, she assumes it’s a hoax.

Lieutenant Abby Mullen is no stranger to crisis. As the hostage negotiation instructor for the NYPD, she deals with worst-case scenarios every day. Nothing fazes her anymore. That all changes when she gets a call from Eden Fletcher, a fellow survivor of the infamous Wilcox cult. The two haven’t spoken since the night of a tragic, fiery massacre, when their paths diverged. But now Eden needs Abby’s help: someone has kidnapped her son and is demanding a $5 million ransom. As Abby throws herself into the case, she can’t help but wonder why the kidnapper has targeted Eden.