It's not clear why a murder charge was filed against Williams.
Authorities said at least one of the gunmen fired their weapon, striking Onfroy.
The investigation is ongoing and detectives said were still seeking a man named Robert Allen, a 22-year-old described as a person of interest in the case.
Williams was allegedly driving an SUV that cut off the rapper's BMW as he attempted to leave the parking lot of the motorsports store, according to Williams' arrest warrant. Investigators want to find out what he knows about the murder.
11 pulled from Alaska plane crash
The pilot was flying from Prince of Wales Island and bound for Ketchikan when the crash occurred, according to the Troopers. One MH-60 Jayhawk helicopter was already headed to the scene from Air Station Sitka, with another being dispatched.
The 22-year-old was already in Broward County Jail after his arrest Thursday on felony cocaine possession with intent to sell or deliver and misdemeanor marijuana possession charges, which brought additional violation of probation charges.
In 2015, he was arrested on drug charges after being found with PVP and Cannabis, according to his rap sheet. After reportedly blocking the vehicle, two more men who were inside the SUV robbed the rapper, whose given name is Jahseh Dwaye Onfroy, at gunpoint. Before his death, he signed a $10 million deal for his third album's release, reported the New York Times, citing three people briefed on the deal.
Not helping calm the masses, Soldier Kidd posted a "Boomerang" photo on his Instagram story. He was shot outside a Deerfield Beach motorcycle dealership.
The image featured a takeout container sitting next to a handgun.
XXXTentacion's hit "Sad", rose to No. 1 on the Billboard Hot 100 charts following his death. The videos were uploaded to social media and quickly went viral.