Rick Thornton is a detective with the Los Angeles Police Department's Robbery-Homicide Division, and the partner of Kizmin Rider. He had an unauthorized informant relationship with Judy Surtain, a TV newscaster. After Harry Bosch and Jerry Edgar questioned Nicholas Trent, Thornton told Surtain that Trent was a suspect and had a prior record as a pedophile. This was widely reported in the media, resulting in Trent's suicide. Thornton's duplicity was revealed as a result of a trap set by Bosch. Thornton was forced to resign from the department.