Prosecutor rules Bonneville County Deputies acted in self-defense in shooting

IDAHO FALLS, Idaho - The Bonneville County Prosecuting attorney has ruled that two deputies from the Bonneville County Sheriff's Office acted in self defense in a officer-involved shooting that happened last month.

Bonneville County Prosecuting Attorney Randy Neal determined the deputies’ use of deadly force was justified as self-defense following the Sept. 4 shooting that killed 43-year-old Marcus J. Griffin of Idaho Falls.

Details of Case

The shooting happened shortly 6 a.m. at a home on Badger Creek Road. According to the Bonneville County Sheriff’s Office, Griffin had called dispatch and said he was armed and was experiencing suicidal thoughts.

When deputies arrived, Griffin’s parents met them at the door and told them Griffin was downstairs and intoxicated.

Deputies Chris Demastus and Jake Mann initially spoke with Griffin from the top of the basement stairs. They could not see exactly where Griffin was or determine his condition.

According to the sheriff’s office, Griffin told deputies not to come downstairs because he was armed. He later told them he would not shoot a deputy if an officer came down.

As deputies descended the stairs, Demastus saw Griffin across the room holding a handgun. The deputies moved back toward the top of the stairs and continued talking with Griffin.

The sheriff’s office says the deputies spent nearly 10 minutes trying to de-escalate the situation as additional deputies arrived and Griffin’s parents were moved to safety.

During the standoff, Griffin made several threatening and suicidal statements, including saying he would come upstairs and shoot the deputies.

According to the sheriff office's account, Griffin eventually appeared at the bottom of the stairs holding the handgun.

Deputies ordered him to drop the weapon, but Griffin refused and moved out of their view.

He appeared again with the gun, prompting deputies to continue giving him commands.

The sheriff’s office says Demastus fired one round toward Griffin during that encounter before Griffin moved out of view.

Griffin appeared a third time, and deputies say he pointed the handgun at them.

Both deputies fired.

The sheriff’s office says Griffin also fired one round toward the deputies, with the bullet striking a wall near the stairs.

Griffin was struck by deputy gunfire and was incapacitated at the bottom of the stairs.

Deputies immediately began lifesaving measures. First responders later arrived, but Griffin was pronounced dead at the scene.

No deputies or Griffin’s parents were injured.

Task Force Investigation

The East Idaho Critical Incident Task Force investigated the shooting, with the Jefferson County Sheriff’s Office serving as the lead agency. Idaho State Police, Idaho Falls Police and other law enforcement agencies assisted with the investigation.

After reviewing the investigation, Neal determined the deputies' actions were legally justified.

Neal said Griffin’s actions presented a real and significant threat of death or serious injury to the deputies. His review concluded that the deputies had probable cause to believe they were facing a deadly threat.

The ruling means Demastus and Mann will not face criminal charges related to the shooting.

The prosecutor's review is specifically focused on whether the deputies' actions constituted criminal conduct. It does not necessarily address separate questions such as whether the deputies' actions complied with department policy or whether different tactical decisions could have been made.

The incident is another example of a law-enforcement response involving a person experiencing a suicidal crisis. The sheriff’s office included information about the 988 Suicide & Crisis Lifeline in its release.