Investigators say Boatwright and Newsome were the two armed suspects who confronted XXXTentacion.
Williams was arrested on June 20, while Boatwright was arrested on July 5 on unrelated drug charges. He was later arrested in connection with first-degree murder while in jail, investigators said.
Allen and Newsome are still at large.
Anyone with information is asked to contact the BSO homicide detectives John Curcio or Walt Foster at 954-321-4210. Anonymous tips can be submitted by contacting Broward Crime Stoppers at 954-493-TIPS (8477) or online. Anonymous tips that lead to an arrest may be eligible for a reward of up to $3,000.