LOS ANGELES — After three years chasing down a serial killer, Dennis Kilcoyne spends his retirement growing lilacs.

As a detective with the Los Angeles Police Department, Kilcoyne led the “800 Task Force” (named after the same room at headquarters) tasked with finding a serial killer. After a stretch of murders in the 1980s, the trail went cold until 2008 when bodies of young black women were being found again in South Central L.A.

The serial killer was back; the “Grim Sleeper” was awake.