Green’s Dictionary of Slang

(US Und.) a receiver of stolen goods.

1931		G. Milburn ‘Convicts’ Jargon’ in AS VI:6 441: stop, n. A receiver of stolen goods; the modern term. ‘Fence’ is no longer used.
1950		Goldin et al. DAUL 213/1: Stop. (Extremely rare) A buyer of stolen goods.