Man convicted of manslaughter, another acquitted in 2022 killing

In the case of a brutal Ridgecrest killing where a man was found beaten and shot in the head, one defendant was found guilty Tuesday of involuntary manslaughter while the other was not guilty of all charges.

Brian Matthew Coykendall, 31, and Erwin Moore, 30, were originally charged with first-degree murder in the killing of Matthew Ian Petersen, 43. Moore was also charged with recklessly evading police.

Coykendall was found guilty of involuntary manslaughter while Moore was acquitted of murder and recklessly evading the police.

According to the probable cause statement the Ridgecrest Police Department submitted to Kern County Superior Court, Coykendall was dating Petersen’s ex-girlfriend Jessica Adams, also referred to as Eva Adams throughout the trial, and the pair were living in Petersen’s house while he was in prison.

Petersen spent time in Wasco State Prison for owning firearms as a felon. He was previously found guilty of multiple charges including battery of Adams and willful cruelty to her child.

On March 4, 2022, Petersen died from multiple head injuries in front of the house he owned on Porter Street in Ridgecrest, according to the Kern County coroner’s office. According to the statement, police found Petersen beaten and face down with a gunshot wound to the head.

On the night of the killing, Moore sped off in a dark-colored car and police chased the car, according to the statement. When Moore stopped, police found two guns in his car. The statement said Coykendall was later identified in connection with the murder and was also arrested.

During closing arguments last week, the prosecutor, Deputy District Attorney Christine Antonios, said Coykendall had planned to kill Petersen when he got out of prison. She said he called Moore for backup and he drove 150 miles from San Clemente to help Coykendall.

However, T. Alan Rogers, Coykendall’s defense attorney, said his client was trying to protect himself and his family from Petersen. Rogers said Coykendall’s actions were in self-defense and were reactions to something Petersen did first, Rogers said.

Moore’s defense attorney, Mark Anthony Raimondo, said Moore came to Ridgecrest after Coykendall told him he needed help. Raimondo said Moore was not a violent person and he had no motive to kill Petersen.