Memorial for slain officer. (Los Angeles Times)

A Riverside police officer slain last month after pulling over a trucker was hit several times in the head with a metal bar before being shot, according to new court records.

Officer Ryan Bonaminio's death was caused both by the gunshot and the beating, according to the records, which were obtained by the Riverside Press-Enterprise.

Prosecutors allege the officer pleaded for his life before he was fatally shot by a state prison parolee who had led the patrolman on a high-speed pursuit and foot chase. Riverside County Dist. Atty. Rod Pacheco last month filed a first-degree murder charge against Earl Ellis Green, 44.

Bonaminio was chasing Green through the city's Fairmount Park when he slipped and fell and, while in a "vulnerable position," he was attacked by Green and had his gun taken away, police have said.

The murder charge includes two special circumstances that make Green eligible for the death penalty: the murder of a police officer and murder to avoid imminent arrest. Green also was charged with vehicle theft and possession of a firearm by a felon.