LOS ANGELES (CBSLA.com) — Arraignment was postponed Thursday for a suspected Mongols motorcycle gang member accused of fatally shooting a Pomona police SWAT officer at a home in San Gabriel.

David Martinez, 36, wore a paper gown that inmates who are being held under suicide watch typically wear during his court appearance Thursday, when his arraignment was rescheduled for Dec. 3.

The suspected Mongols motorcycle gang member was charged with capital murder for the Oct. 28 shooting of 45-year-old Officer Shaun Diamond, who was helping to serve a search warrant when he was shot. The criminal complaint also includes gun and gang allegations.

Prosecutors have not yet decided whether to seek the death penalty for Martinez.

Los Angeles County sheriff’s officials said Diamond was helping to open the outer door of a home in the 100 block of San Marino Avenue as part of a multi-agency operation targeting the Mongols gang when an interior door of the home was opened and a single shotgun blast rang out.

Diamond was shot in the back of the head and died the following day. Martinez was taken into custody at the scene.

Martinez’s criminal history includes assault with a deadly weapon and domestic violence, authorities said.

Diamond was a 16-year law enforcement veteran. He worked with the Los Angeles Police Department from 1195-2002, then with the Montebello Police Department from 2002-03. Diamond joined the Pomona Police Department in 2006 and its SWAT team two years later.

Diamond was survived by his wife, a son, daughter, mother, father, sister and brother. He was buried last week.

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