Deschutes County prosecutors are seeking an enhanced prison sentence for the man accused of plotting to shoot rock climbers at Smith Rock State Park.

If convicted of the most serious charges — attempted murder — and the state proves there are “aggravating factors” in his case, Samson Zebturiah Garner, 39, could face a minimum of 10 years in prison as opposed to 90 months, said Deschutes County District Attorney Steve Gunnels.

“We believe that the conduct is of such a nature that a significant penalty is appropriate if he’s convicted,” said Gunnels on Wednesday.

Garner is charged with 27 felony counts for allegedly planning to kill spectators and belayers at an event at Smith Rock on Oct. 19, including four counts of attempted murder.

Charges: Multnomah County man charged with planning mass shooting in Deschutes County

Suspect arrested in Tumalo

Garner was arrested Oct. 19 outside his Subaru near Tumalo after authorities said he drove from Multnomah County to Central Oregon with guns in his car, including an AR-15 rifle. Law enforcement officials also obtained written material that allegedly included his plans to shoot and kill rock climbers at Smith Rock, one of the nation’s most well-known rock climbing destinations, Gunnels previously told The Bulletin.

The American Alpine Club and Smith Rock State Park Manager Matt Davey each said law enforcement authorities contacted them about a threat against attendees to the Smith Rock Craggin’ Classic, a three-day climbing event that draws hundreds of people annually. It was scheduled the weekend of Garner’s arrest.

In a Nov. 15 filing in Deschutes County Circuit Court, Garner’s defense attorney, Joel Wirtz, said his client is accused of “attempting to murder multiple persons based upon an email he may have sent.” Wirtz did not respond Wednesday to a request for comment.

Garner has pleaded not guilty to all counts.

Prosecutors looking for ‘enhancement facts’

Oregon sets guidelines around what sentences accompany specific crimes. The latest move by prosecutors would allow the court to impose a penalty outside those guidelines based around certain evidence that prosecutors call “enhancement facts.”

Gunnels declined to specify exactly what evidence prosecutors have obtained that would justify a greater penalty. He said the move from the prosecution is not unusual and noted authorities seek similar adjustments to penalties in other cases.

But the prosecution’s Dec. 11 filing alleges the existence of “substantial and compelling aggravating factors.”

Garner allegedly intended to inflict “catastrophic physical and mental harm to the victims and witnesses” and “delay and defeat emergency law enforcement response by using armor penetrating ammunition,” the filing states.

He also allegedly selected “a location and event” to maximize “harm to victims by preventing quick emergency medical and law enforcement response” and “committed the offense after substantial planning and premeditation to cause the death of a person or commit an act of terrorism,” the filing also states.

“The degree of harm or loss attributed to the current crime of conviction was significantly greater than typical for such an offense,” the filing states.

Records: Suspect in plot to kill Smith Rock climbers fantasized about Mt. Hood attack

Suspect’s friends alert authorities

According to records previously reported by The Bulletin, Garner twice became the subject of police scrutiny after friends reported that he was armed and making disturbing statements, including fantasies to shoot and kill people at Mt. Hood Meadows ski area.

One friend reported a Sept. 30 email to police in which Garner wrote about killing rock climbers at the Smith Rock Craggin’ Classic climbing event, saying “how easy it would be to rampage through the park shooting belayers and spectators while their climbers watched and lived the horror,” records show.

Garner’s trial is scheduled for May.