Green’s Dictionary of Slang

(US black) a police officer or the police as an institution.

1985		T.R. Houser Central Sl. 39: one time The police ‘Cause you all be swoopin one time’.
1990		Boo-Yaa T.R.I.B.E. ‘Psyko Funk’ 🎵 Before the one-time could pick us up, we had already moved the crowd.
2000		Ebonics Primer at www.dolemite.com 🌐 one-time Definition: law enforcement officials, police Example: One-time be on my ass an’ shit for dat 187.
2012		‘Dutch’ ? (Pronounced Que) [ebook] You know why them Cali nigguhs call police ‘one time’? ’Cause we can get away a thousand times, but it only takes them one time.