The riff: Opined by Tom as Jimmy, the nebbish loser salesman, puts a record on the record player.
The explanation: I believe he’s referring to the song “Cop Killer” by the hardcore rock band Body Count, from their eponymous 1992 album. The group, fronted by rapper Ice-T, scored a very controversial hit with the song, which was about a disillusioned inner city gangster who decides to combat police brutality by striking back at the cops with deadly force. Ice-T eventually removed the song from the record in response to the protest, but it continues to be performed live.
Novelty factor: I was pretty young when this song was new, but I believe I still remember some of the buzz that it caused. I expect it was probably played for me at friend’s houses due to its “banned” nature.