Convicted murderer Jeffrey Scott Serio received a 100-year prison sentence Wednesday for intentionally running over and killing a Flathead Valley man in the summer of 2025.  

“The seriousness of the crime is that you used a motor vehicle and accelerated directly toward the victim, running him down and inflicting a fatal trauma,” said Judge Heidi Ulbricht as she handed down the sentence in Flathead County District Court on Aug. 12. “The degree of this violent escalation demonstrated an extreme indifference to human life.” 

A jury found Serio, 49, guilty of deliberate homicide following an eight-day trial in May. Serio had unsuccessfully argued that he killed Raymond Maurice “Mory” Grigg on the latter’s Birch Grove Road property on Aug. 19, 2025 in self-defense.  

Serio had trespassed on Grigg’s property several times that day, according to court documents and witness testimony. During their final, fatal encounter, Grigg’s opened fire on Serio’s Toyota Sequia as it tore across his land. 

Serio fled on foot after the collision, leaving Grigg pinned beneath the vehicle. Authorities pronounced him dead at the scene. 

Grigg’s friends and relatives on Wednesday described his death as traumatizing and said his absence had left a gaping hole in their lives.  

“I was the one who saw his body under the car,” testified Grigg’s sister Cherice Dahlin. “I saw just his foot and just his shoe and so I just started screaming because I knew right then and there that he had been killed." 

Dahlin, who was visiting Grigg’s home for a pizza party on the night of his death, recalled her brother as kind, patient and open-minded. The two worked together closely and had a list of projects on their to-do list so long that would have taken a lifetime to check off, she said.  

“We’ve lost the future,” she said. “I lost the future with him." 

Grigg’s had a wide circle of friends all across the country, she said. Even now, nearly a year after his death, she is still breaking the news to acquaintances of his.  

Seirra Born, who rented a home from Grigg with her mother, described him as a father figure to her. She expected him to walk her down the aisle at her wedding, she said.  

“Losing him meant losing the person who stepped into the role of father,” Born said before a sob overtook her.   

“And provided me with guidance, support and unconditional care,” she finished a moment later, clutching a tissue.  

WHEN IT came his turn to speak, Serio offered a few words of apology for Grigg’s death.  

“... I feel bad about what happened and all the people that it hurt,” he said, sitting at the defendant’s table in an orange inmate’s uniform, the white sleeves of an undershirt poking out. “If I could take it back, I would. And I’m truly sorry.” 

His defense attorney, Alisha Rapkoch, sought to highlight Serio’s troubled state of mind prior to the fatal confrontation with Grigg. Putting his mother, Irene Serio, on the witness stand, Rapkoch walked the courtroom through two trips to the emergency room and multiple attempts to involve law enforcement personnel as Serio’s behavior and health worsened in the days preceding the murder.  

“You ... continued to ask for help because you were worried about the condition your son was in?” Rapkoch asked Irene Serio.  

"Yes,” she replied. “We wanted help.” 

But Deputy County Attorney Amy Kenison, who prosecuted the case alongside Deputy County Attorney Ashley Frechette, used Irene Serio’s time on the stand to underscore her son’s history of substance abuse and aggressive behavior.  

Irene Serio denied her son continued to struggle with drugs and alcohol, although she acknowledged he was on suboxone after turning to opioids following the death of his wife in 2017. The couple had previously lost a child. 

He had two prior driving under the influence convictions, Kenison said before asking Irene Serio if he struggled with anger as well. When she denied it, Kenison reminded her that she and her husband had sought a restraining order against him after he broke into their camper and pushed them.  

In a separate, earlier incident, Serio had fired a gun into a mattress, Kenison said.  

KENISON RECOMMENDED that Ulbricht hand down a 100-year sentence and asked that she designate him a violent offender.  

“This was not self-defense. This was a choice made by the defendant,” she said of the murder. 

Rapkoch, meanwhile, petitioned Ulbricht for a 10-year sentence in Montana State Prison for her client, pointing to his deteriorating state of mind and the lengths his parents went to secure help for him.  

“[Serio] and his family did try to get help,” she said. “They tried to figure it out.” 

Before handing down the sentence, Ulbricht noted Serio’s lack of criminal convictions and good behavior while in the county jail.  

But she pointed to the past incidents of violence involving his parents and emphasized his repeated decision to mix suboxone with alcohol and other drugs.  

And Grigg’s death was a “great loss to his family, friends and the community,” Ulbricht said.  

Along with the sentence, Serio was given credit for 359 days of time served and ordered to pay $6,160 in restitution.  

News Editor Derrick Perkins can be reached at 406-758-4430 or [email protected]. If you value local journalism, pledge your support at dailyinterlake.com/support.

    Jeffrey Scott Serio is shown at his sentencing hearing in Flathead County District Court on Wednesday, Aug. 12. (Casey Kreider/Daily Inter Lake)
 Casey Kreider