Pico Rivera (courtesy latimes.com)

L.A. County Sheriff’s photo of a 22-year-old Pico Rivera gangster Anthony Garcia, with a tattoo of the scene of a liquor store murder that had puzzled deputies for more than four years. All the details of the unsolved killing right there on the killer’s chest: the Christmas lights that lined the roof of the liquor store where 23-year-old John Juarez was gunned down, the direction the shots were fired, the bowed street light across the way and the street name, all sketched out under a chilling banner: RIVERA KILLS, a reference to Rivera-13, the man’s gang. As if to seal the deal, below the collarbone of the gang member known by the alias “Chopper” was a miniature helicopter raining down bullets on the scene. The 2008 discovery was the beginning of a bizarre investigation that sent sheriff’s investigators, posing as gang members, into Anthony Garcia’s cell posing as fellow gangsters. There they got a jailhouse admission that this week led to a conviction in a killing that investigators had all but