"Sound of da Police" is the second and final single from rapper KRS-One's first solo album, Return of the Boom Bap. The song begins with KRS-One whooping twice to evoke a police siren (the "sound of the police"); this recurs several times throughout the song. This song was used in the trailer for Cop Out. "Sound of da Police" was released as a CD single featuring a b-side, "Hip-Hop vs. Rap". The song is produced by Showbiz from DITC. The heavy bass sample loop was taken from Grand Funk Railroad's cover of Inside-Looking Out, the final track their not quite eponymous LP Grand Funk (album).