WEST PALM BEACH, Fla. (AP) — Police in Florida are searching for clues after a Saturday night shooting on Interstate 95 in South Florida that left University of Alabama Birmingham running back Gregory Bryant brain dead and injured a passenger in his car.

Police spokeswoman Lori Colombino said in a statement that 21-year-old Bryant was taken to the hospital in critical condition and declared brain dead on Sunday afternoon.

Detectives are looking for witnesses to the shooting that happened about 4:45 a.m. Saturday near West Palm Beach.

Bryant started his career at Notre Dame but was declared academically ineligible. He spent last season attending ASA College in Miami, where he played in just one game. He transferred to UAB earlier this year, and was the biggest name in UAB’s first recruiting class since the school restarted its football program.

Because UAB won’t play again until the 2017 season, Bryant was allowed to enroll in classes in January and could have become eligible to play after spending an academic year at the school.

His grandmother, Annette Kelley, told WPEC that Bryant came home for Mother’s Day weekend and was getting ready to return to college in Alabama. She said they are looking for answers because “a coward killed my baby.”

In Birmingham, Alabama, teammates were mourning what happened to Bryant.

“This guy did a complete 180,” said Timothy Alexander, the life coach for UAB’s football team, told WBRC (http://bit.ly/1YgVb1S ). “People counted Greg out. Greg counted himself in. It shows what one man can do when you believe in yourself.”

Alexander had been scheduled to pick up Bryant from the airport on Sunday.

“This is our brother. It’s someone’s son, it happened to this man’s mom on Mother’s Day. It hurts,” Alexander said.

No one has been charged, but West Palm Beach Police are investigating the case as a homicide.