Complex sentence: Stringer already knows that Greggs was a cop and orders Wee-Bey to kill Little Man and tells Wee-Bey he might need to leave town if the police begin to close in.
Split into simpler sentences: Stringer already knows that Greggs was a cop and orders Wee-Bey to kill Little Man. He tells Wee-Bey that he might need to leave town if the police begin to close in.