LOS ANGELES (AP) — A suspected Mongols motorcycle gang member was charged with murder Thursday in the killing of a Pomona SWAT officer during a crackdown on the group.

The charge against David Martinez, 36, included special circumstances that could bring the death penalty, but prosecutors had not yet made that decision.

Martinez remained jailed without bail, and it was not immediately clear whether he had an attorney. His arraignment was postponed to Nov. 13.

Prosecutors contend that Martinez fired a shotgun and struck Officer Shaun Diamond in the back of the head as he helped serve a search warrant Tuesday in suburban San Gabriel.

The same shotgun blast also struck Martinez’s father in the arm, authorities said.

Diamond, a 19-year law enforcement veteran, was taking part in a multi-agency operation targeting the Mongols. He died Wednesday.

Diamond was the fourth California law enforcement officer killed in the line of duty in less than a week.

Ventura County sheriff’s Sgt. Eugene Kostiuchenko was struck by a suspected drunken driver during a freeway traffic stop. Last week, a Sacramento County sheriff’s deputy and a detective from Placer County were shot to death in attacks that ended with two Utah residents being charged with murder.