Kalispell man sentenced to 100 years for killing man by running him over

According to court documents, on Aug. 19, 2025, deputies with the Flathead County Sheriff’s Office responded to reports of a suspicious man on a property in Kalispell near the Glacier Park International Airport. A deputy arrived to find Serio on the scene, who said his vehicle was parked nearby. After being told to leave the property, Serio did so, leaving for his parked vehicle.

While leaving, documents state, the deputy heard what sounded like a rapidly accelerating car driving through a nearby cornfield, then saw the car driving through a fence. The deputy then heard gunshots.

More deputies responded immediately and found Grigg trapped underneath Serio’s vehicle. Witnesses stated Serio was driving toward Grigg’s house through the neighboring field, that they’d heard gunshots, and that Serio had gotten out of the vehicle and left the scene. Serio was found soon after. 

Law enforcement located five shell casings at the scene. Two rounds had hit the front of Serio’s car.

Friends and family of Grigg said at sentencing that they'd been at Grigg's property for a gathering when the homicide happened.

"We were very close," Grigg's sister Cherice Dahlin said. "I've lost the future with him." 

She said people from six different states came to the funeral, and she's still breaking the news to Grigg's friends that he was killed. 

Serio's mother testified at the sentencing arguing for leniency, saying that Serio had been suffering from delirium in the time before the homicide, had suffered the loss of a child, and hadn't been helped by law enforcement with his medical issues. 

Prosecutor Amy Kenison argued for a 100-year sentence.

"Everyone experiences some sort of loss," she said. "While we can empathize with the defendant's loss, it doesn't give him the justification to take another's life." 

Defense attorney Alisha Rapkoch argued for a more lenient sentence.

"He wasn't out there trying to deliberately kill him or run him down or anything like that," she said.

Serio himself addressed the court briefly.

"I feel bad about what happened and all the people that I hurt," he said. "If I could take it back I would, and I'm truly sorry." 

Ulbricht then imposed the sentence of 100 years in the Montana State Prison.