An anonymous tip predicts a murder. The detective who responds becomes the prime suspect.

Detective Mara Lin is the best investigator in the Homicide division, disciplined, precise, and built on clean cases. When an anonymous tip arrives through the department’s official hotline predicting a killing with uncanny accuracy, she responds. The victim is found exactly as described. Then a second tip arrives. A second body follows.

The media calls the tipster “The Oracle Caller.” Internal Affairs asks a different question: why is Detective Lin always first on scene?

The investigation turns inward.

As Mara traces the tips through the department’s own digital infrastructure, she discovers the predictions aren’t coming from outside. Someone with insider access is using the system she trusts to announce murders, and to build a case against her. Her partner is reassigned. Her access is restricted. Her reputation is dismantled in the press.

Suspended and stripped of her badge, Mara refuses to stop. Working from memory, she uncovers a connection between the victims that reaches back years, to a sealed corruption inquiry, a compromised trial, and a departmental secret that someone will kill to keep buried.

The system was designed to protect. Now it’s being used to destroy.

Tipline Zero is Book 2 of The Integrity Files, a series of standalone procedural crime thrillers examining what happens when identity is manipulated and institutions turn against the people they serve. Each book features a different lead detective and can be read in any order.

For readers who love Michael Connelly’s Bosch, Robert Dugoni’s Tracy Crosswhite, and Tana French’s Dublin Murder Squad.