“Thirteen” (Flatiron Books), by Steve Cavanagh

The tag line to Steve Cavanagh’s fourth novel about former con man turned defense lawyer Eddie Flynn is, on its own, tantalizing: “The serial killer isn’t on trial he’s on the jury.”

But Cavanagh’s “Thirteen” is no gimmick. It’s a superb action-packed story that melds the legal thriller with the serial killer subgenre, featuring intriguing character studies of both heroes and villains and a perceptive look at the legal system.

Eddie sees a lot of similarities between his old life as a con man and his career as a lawyer, especially in dealing with juries. But the main difference is that Eddie is now scrupulously honest, willing to take on anyone, including corrupt cops. As a result, his practice is rather low-rent. His apartment is his office, and he advertises on the side of a hot-dog cart. He’s stunned when high-powered attorney Rudy Carp wants him to join the team defending up-and-coming actor Bobby Solomon, who’s accused of killing his wife, the popular actress Ariella Bloom, and Carl Tozer, the couple’s chief of security. The victims were found murdered in bed in the actors’ Manhattan home.

Irish author Cavanagh nails the New York vibe while illustrating an affinity for American legalese. Cavanagh delves deep to show how Kane manipulates the jury and how he has stayed under the radar of law enforcement for years. The number 13 becomes a chilling totem as Eddie begins to put together evidence and clues. “Thirteen” seamlessly alternates from the viewpoints of Eddie and Kane. Cavanagh shows how the highly intelligent Kane became a killer, yet the author never wants the reader to feel empathy or sympathy for him. Kane’s self-assuredness makes him forget the rule of never conning a con man.

Sharp dialogue, court scenes that crackle, well-devised red herrings and deeply sculpted characters make “Thirteen” an outstanding thriller.