LOS ANGELES » A 16-year-old has been charged as an adult in the shooting death of a Southern California police officer in what investigators called a botched robbery.

The teen, Abel Diaz, was charged Friday with murder in the death of Downey police Officer Ricardo “Ricky” Galvez.

A court appearance for Diaz set for Friday was postponed until Monday. He faces life in prison if convicted.

Two other suspects — 18-year-old Steven Knott and 21-year-old Jeremy Anthony Alvarez — are expected to be charged Monday.

It was not clear whether any of the three has an attorney.

The 29-year-old Galvez was in plainclothes in the driver’s seat of his personal car at the end of his shift Wednesday night when he was shot.

The former Marine, a five-year veteran of the police department, died in his car.