A 22-year-old man is being sought over the fatal shooting of rising rap star XXXTentacion in Florida.

Broward Sheriff's Office spokeswoman Veda Coleman-Wright said that detectives want to ask Robert Allen what he knows about the rapper's death.

She said he is also wanted on a warrant for violating probation for possession of drugs and carrying a concealed weapon.

XXXTentacion, whose real name is Jahseh Dwayne Onfroy, was shot on June 18.

Detectives said a SUV blocked the 20-year-old rapper's luxury sports car in the driveway of a Fort Lauderdale area motorcycle dealership and two masked men confronted him during an apparent robbery attempt.

Twenty-two-year-old Dedrick Williams faces murder charges. He has not yet entered a plea.