Bryant playing for his former team at Notre Dame in 2014.
The 21-year-old football player and a passenger named Maurice Grover were found shot in a car on Interstate 95 around 4:45 a.m. on Saturday morning, police confirmed.
Grover survived with minor injuries, but Bryant was taken to a hospital and pronounced brain dead around 1 p.m. local time Sunday.
West Palm Beach Police told BuzzFeed News in a statement they had reclassified their investigation as a homicide.
The cause of the shooting was unknown, and so far no suspects have been identified.
Detectives are currently searching for witnesses, police said.