PHILADELPHIA (AP) — A 4-year-old boy was shot and killed in Philadelphia early Thursday in what his father told police was a home invasion robbery, authorities said.

Police went to the home shortly before 1 a.m. in response to a 911 call.

The officers were met by the boy’s father, who was on the ground floor and holding another child. The wounded boy was found in an upstairs room, but he was unresponsive and was pronounced dead a short time later at a hospital.

The father, whose name has not been released, told authorities that he and the two young children were in the house when the home invasion occurred, and the children’s mother was at work. The father and the younger child were not injured.

Acting Philadelphia Police Commissioner Christine Coulter said investigators were interviewing the father in a bid to get “a clearer picture” on what happened. She said the father reported that it was a home invasion robbery when he called it into police and to the first responding officers.

It wasn’t immediately clear why the child was shot or if anything was taken from the home, authorities said.