Ex-Marine gets probation for Ridgecrest homicide

BAKERSFIELD, Calif. (KGET) — A former U.S. Marine found guilty of involuntary manslaughter in the 2022 death of a man in Ridgecrest was sentenced Thursday to two years’ probation.

Brian Coykendall, 34, had faced a murder charge at his trial last month but jurors convicted him of the lesser charge of involuntary manslaughter.

Man guilty of murder in Lamont crash that killed 3 women

His co-defendant, Erwin Moore Jr., 30, was acquitted.

The two were accused of killing Matthew Ian Peterson on March 4, 2022. Peterson, 43, was severely beaten and shot once in the back of the head, a prosecutor said.

Defense attorneys at trial argued Peterson was accidentally shot in a struggle over a gun. A prosecutor said the killing was planned in advance.

On Thursday, Deputy Public Defender T. Alan Rogers, Coykendall’s attorney, asked that the court sentence his client to probation. He said Coykendall suffers from post-traumatic stress disorder from his service in Afghanistan, which should be considered a mitigating factor.

“The goal here is to punish someone, but it’s also to rehabilitate them,” Rogers said.

Prosecutor Christine Antonios argued Coykendall should be sentenced to a four-year prison term. She acknowledged he had enough custody credits to fulfill the sentence and be placed on parole, but said parole restrictions were more appropriate than probation.

In deciding on probation, Judge Kenneth C. Twisselman II said he found it significant Coykendall wrote a letter expressing remorse and wishing Peterson’s children still had their father. Twisselman said he believed the letter was sincere. He said in many cases defendants refuse to admit wrongdoing or show remorse.

The judge told Coykendall this sentence gives him an opportunity to get his life back on track. He said he hopes Coykendall completes probation, gets whatever treatment is necessary for his PTSD and stays out of trouble.


Peterson and Coykendall were once friends. But after Peterson went to jail, Coykendall started dating his girlfriend.

Never miss a story: Make KGET.com your homepage

Antonios said at trial Coykendall hatched a plan to kill Peterson if he returned to Ridgecrest. The evidence, she said, suggested Coykendall and Moore had an agreement in which Moore — who lives outside the county and was also a Marine — would drive to Ridgecrest and assist Coykendall in the slaying.

When Peterson’s body was found shortly after his death, his hands were bound behind his back. Surveillance video, while not showing what happened, captured his screams for help.

Moore’s attorney, Mark Anthony Raimondo, told the jury a fight broke out between Coykendall and Peterson after Moore arrived, and when Moore tried to break it up a gun fell from his waistband.

There was a struggle over the gun, he said. It went off, and the round struck Peterson.

Copyright 2024 Nexstar Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

For the latest news, weather, sports, and streaming video, head to KGET 17.