A 21-year-old man is in custody in Florida — accused of throwing his ex-girlfriend's 3-month-old son from his car on an interstate highway.

The body of the child was found near Interstate 275 north of downtown Tampa early today.

Police captured Richard McTear several hours later. He's charged with first-degree murder and other charges.

According to police, McTear had been arguing with his 17-year-old ex-girlfriend at her apartment when he began beating her and the child. She told authorities that McTear threw the baby down on the concrete, then picked him up and fled in his car.

A TV news photographer spotted the baby's body on his way to work.

A sheriff's spokeswoman says the medical examiner's office will determine at what point the baby died.

Police say McTear is not the baby's father.