SAN DIEGO -- Authorities say a woman found dead in an apartment alongside a man suspected of killing a San Diego police officer was killed by a bullet wound to the head and her death has been ruled a homicide.

The San Diego County Medical Examiner said in a statement Saturday that 27-year-old Lucky Xayasene died from a "penetrating gunshot wound to the head," but did not say who fired the bullet.

Police say Xayasene and 30-year-old Holim Lee were found dead Thursday in a bedroom littered with guns, hours after gunfire was exchanged with officers and U.S. Marshals serving an arrest warrant at the apartment. Officer Christopher Wilson was shot and killed.

The coroner's statement did not give a cause of death for Lee, whose family says he served in the Coast Guard but later turned to drugs and crime.