LOS ANGELES (CBSLA.com) — A judge postponed arraignment Monday for three suspects accused of killing a 29-year-old Downey police officer during a botched robbery.

Steven Knott, 18, and Jeremy Anthony Alvarez, 21, were scheduled to be arraigned along with 16-year-old co-defendant Abel Diaz after 1:30 p.m. in Downey at Los Angeles County Superior Court.

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KNX 1070’s Jon Baird reported the arraignment was postponed until Dec. 17.

The three defendants are each charged with one count of special circumstance murder and one count of attempted second-degree robbery. The amended complaint includes the special circumstance that the murder occurred during an attempted robbery.

Prosecutors will ask that each defendant be held without bail.

Authorities said Diaz is turning 17 years old next week. He has been charged as an adult and his bail has been set at $1 million.

Knott and Anthony were identified as the other two suspects as brothers on Friday, according to the Downey Police Department.

Ricardo “Ricky” Galvez, a five-year veteran of the Downey Police Department, was shot to death Wednesday night as he sat in his personal vehicle in a parking lot adjacent to the police station.

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Diaz, Knott and Anthony are accused of approaching the vehicle and opening fire on Galvez.

Police said the suspects are believed to have been were unaware that Galvez was an officer as he was not in a marked police cruiser.

Galvez only returned to the station to use the restroom before driving home from K-9 training at another location.

A handgun believed to have been used in the murder was recovered at the scene.

A friend revealed that Knott, who was an aspiring rapper, was going to be going on tour through Utah, Oregon and northern California, starting just two days after the shooting occurred.

Detectives are reviewing security video as the motive for the deadly shooting remains under investigation.

If convicted, Knott and Alvarez could face the death penalty. Diaz, because of his age, faces up to life in state prison if convicted as charged.

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The case remains under investigation by the Los Angeles County Sheriff’s Department.