An 18-year-old man surrendered to police late Tuesday afternoon and was booked on suspicion of murdering his girlfriend in the bedroom they shared at his grandparents' Covina home.
Joseph Anthony Gutierrez walked into the Covina police station about 4:30 p.m. and turned himself in to detectives investigating the case, Sgt. Dave Foster said.
Gutierrez was being held in lieu of $1 million bail, with arraignment expected Thursday, Foster said.
A motive was unclear, according to the sergeant, who said the suspect was being interviewed by detectives.
Gutierrez's grandfather called police just after 2:25 p.m. Monday, when he heard a gunshot inside the home at 136 S. Brightview Drive and discovered the 18-year-old victim.
Gutierrez was gone when officers arrived and found the young woman in a bedroom. Yazmeen Hassan of Covina was declared dead at the scene of head injuries.
Police said she had recently moved into the home and was sharing a bedroom with Gutierrez.