Williams was arrested in Pompano Beach about 7 p.m. Wednesday following a traffic stop.
Broward Sheriff's Office spokeswoman Veda Coleman-Wright said homicide detectives were also seeking additional suspects in the shooting. While an official autopsy report has not been released, an eyewitness said the "SAD!".
In the video, the rapper said: "It's not cool to make assumptions".
An attorney for Williams isn't listed on jail records.
South Florida rappers Soldier Kidd and Soldier Jojo were initially accused being behind XXXTENTACION's murder on the internet which prompted both of them to share videos denying any involvement. Williams appeared before a Broward County judge, and faces one count for first degree murder. A stream of mourners left mementos at the spot where rapper XXXTentacion was killed as he left a Florida motorcycle dealership.
The alleged shooter was additionally charged with a probation violation for an earlier grand theft auto charge and is being held without bail.
"They kicked me out of the vigil".
XXXTentacion was announced dead on Monday afternoon after the Broward Sherrif's Office said: "The adult male that was taken to the hospital has been pronounced dead". 'I wasn't even there 25 minutes and I literally got pulled away from the memorial'. "I was glad I didn't stay next to him because there was all that 4-wheeler noise going on down there".