The episode was originally planned for airing on April 30 , 1999 , but NBC moved it back one week to put more distance between the show 's gunman/hostage story and the Columbine massacre . A minor continuity error occurs involving Mike Giardello 's character , since he resigns from the FBI in " Identity Crisis " ( the episode moved into the 4/30 spot ) . In this episode , he is referred to as " Officer Giardello . " 1 . Kalat , David P. ( 1998 ) . Homicide : Life on the Street : The Unofficial Companion . Los Angeles , California : Renaissance Books .
Columbine massacre
Columbine High School massacre
Lines of Fire