Two teenagers have been charged with murder in the beating death of a homeless man whose body was found in a southern New Jersey alleyway last week, authorities said.

The 17-year-old girl and 15-year-old boy were both seen on surveillance video entering the alleyway in Camden shortly before Bobby Hill Jr., 63, was killed, according to the Camden County Prosecutor’s Office. They were then seen leaving the area several minutes later.

One of the teens also had cell phone video showing Hill’s body after the beating, prosecutors said.

Hill’s body was found early Thursday. An autopsy determined that he died from blunt force trauma.

A motive for the attack has not been disclosed.

The two teens remained in custody. It’s not known if either youth has retained an attorney.