Vigilante / Stephen J. Cannell.

Enhanced descriptions from Syndetics:

In the last novel by acclaimed producer and New York Times bestselling author Stephen J. Cannell, LAPD detective Shane Scully and his partner Sumner Hitchens investigate a crime with ties to the sometimes violent world of reality TV. Lita Mendez was a thorn in the LAPD's side. An aggressive police critic and gang activist, she'd filed countless complaints against the department. So when she's found dead in her home, Shane and Hitch fear the worst: that there's a killer in their ranks. Outside the crime scene, Nixon Nash, the charismatic host of a hit reality TV show called Vigilante TV, has set up shop with his crew. Nash's show is dedicated to beating the cops at their own game, and now he has the murder of Lita in his sights. He presents the police with a choice: either join his team or prepare for a public takedown. Scully suspects Nash isn't the folk-hero he portrays. The man will do anything to promote himself - perhaps even kill...