CAPITOL HEIGHTS, Md. (AP) _ Four people, including two small children, were killed when a gunman burst into an apartment in this Washington, D.C., suburb early Wednesday.

Michelle Boyd, 21; her sons Deandre, 3, and Jermell, 2, were shot once the head each around 1 a.m. as they slept in a rear bedroom, said Prince George's County police spokesman Cpl. Kenneth Scott.

Investigators believe at least one person burst into the bedroom after shooting 15-year-old Latoya Gibson once in the head when she answered a knock at the front door, Scott said.

The teen-ager, an apparent overnight visitor, died at Children's Hospital in Washington on Wednesday evening.

Detectives questioned the children's father for several hours, but it was not clear whether he was considered a suspect. Scott declined to identify the man, who he said did not live at the apartment, and said it was too early to determine a motive.

Police were called to the residence by neighbors who heard at least two gunshots. It was unclear whether anything was taken from the apartment, according to Scott.