Police in Los Angeles say a young U.S. Marine shot in the city while on weekend leave is unlikely to survive his injuries.

The Los Angeles Police Department says Carlos Segovia was shot once in the back of the head while sitting in a car Friday night. KABC-TV reports police say a vehicle pulled up beside Segovia's Dodge Charger, and one or more people opened fire on Segovia. Police tell the Los Angeles Times that Segovia has little to no brain function.

A family friend tells the Times that Segovia was on leave from Camp Pendleton near San Diego and was visiting family and friends in Los Angeles.

Police say Segovia wasn't in uniform during the shooting, and no suspects have been identified. Investigators don't have a motive.