Judge Amy Eddy flatly rejected Derrick James Jackson’s story of self-defense in the deaths of his mother and her partner while sentencing the convicted killer to 100 years behind bars on Tuesday. 

A Flathead County jury in April found Jackson, 39, guilty of deliberate homicide for the Oct. 28, 2022 murder of 65-year-old Stanley Grotberg, but acquitted him of killing his mother, 62-year-old Tricia DeMotts. Authorities found the pair shot to death in their Bigfork home after arresting Jackson with a gun on a neighbor’s property earlier that day.   

Testifying at the double homicide trial, Jackson accused Grotberg of fetching the gun during an argument and using it on his mother. He recounted holding DeMotts in his lap as she died and later retrieving the gun and turning it on Grotberg, who he claimed charged at him.   

Jackson and his defense team, attorneys Thomas Schoenleben and Levi Roadman, clung to that version of events while arguing for a partially suspended 20-year sentence on June 17.   

Speaking before the court, Jackson began remorsefully, apologizing for his role in what he described as a tragedy. But he soon veered to blame Grotberg for DeMotts’ death.  

“My actions in defending myself caused [Grotberg's] death and that is truly a tragedy ... and now his loved ones have to go through this life without him," Jackson said from the defense table while sniffling. “For that I am so sorry. That is not what I wanted.”  

Then he launched into a lengthy diatribe about Grotberg, who he described as “not a good man,” recounting him previously acting disrespectful around DeMotts and threatening to have Jackson’s father killed. Jackson also mused on how things might have turned out differently had he not been recovering from a car wreck at the time of the killings.   

Eddy intervened as Jackson trailed off disjointedly, his husky voice fading.  

“Is that everything. Mr. Jackson?” she asked, head cocked forward.   

“Yeah,” came the almost inaudible reply.  

Roadman drew on Jackson’s account in seeking a lessened sentence.  

“If [Jackson] didn’t kill his mother, there is one other person that could have,” he said. “It stands to reason if [Jackson] didn’t kill his mother, the jury found it plausible that [Grotberg] did.”  

But Eddy deemed Roadman’s argument fantastical.   

“I understand that the jury found the defendant not guilty of count one, deliberate homicide of his mother Tricia DeMotts. The jury also rejected — as frankly incredulous — the defendant’s theory of self-defense,” she said. “Primarily that DeMotts was shot, that he pulled her into his lap, cradled her on the bed before she was shot again, but had none of her blood on him.”  

She cited Jackson’s criminal history — four felony convictions, seven misdemeanor convictions and eight revocation proceedings — his high likelihood of reoffending, poor behavior while incarcerated, to include a foiled escape attempt, and failed attempts to deceive mental health evaluators at the Montana State Hospital as reasons for the lengthy sentence.   

“In my 10 years on the bench I have never seen a report come back from the state hospital that not only did the defendant not have a mental disease or disorder but was feigning or exaggerating symptoms to avoid accountability,” Eddy said.  

CALLING FOR Jackson to receive the maximum penalty, Eric Grotberg testified that his father’s murder had devastated and traumatized his family. His sons had lost friends over media coverage of the case and struggled at school, he said.  

He had also noticed himself withdrawing from the wider world, Eric Grotberg said.   

“We used to be the household in the neighborhood that all the kids came to, coming out and having fun and everything, and now just I struggle to go outside sometimes to talk to people, interact with people,” he said. “They tell me, ‘You don’t laugh any more, you don’t have fun anymore.’”  

Holidays, like Father’s Day, are difficult, Eric Grotberg said.   

“Instead of being jovial and fun and all of that, I just cry all day,” he told Deputy County Attorney Amy Kenison, who prosecuted the case with Deputy County Attorney Katie Handley.   

The court also heard from Jackson’s father John Jackson, who testified that his son had grown remorseful since the trial.   

“You can sense it,” he said under questioning from his son’s defense attorneys.   

John Jackson told the court he believed his son’s story, that he had killed Stanley Grotberg after Grotberg shot DeMotts dead.   

“He loved his mom,” John Jackson said of his son.   

For Grotberg’s death, Jackson received 80 years in Montana State Prison with an additional 10 years for using a firearm. For tampering with evidence — picked up for ditching the gun used in the shootings — Jackson received 10 years. Eddy ordered the sentences to run consecutively, designated Jackson a persistent felony offender and gave him credit for 952 days of time served.   

“The defendant is a demonstrated threat to the community and it’s in the best interest of the community that he be incarcerated for a significant period of time,” she said.  

As she handed down the sentences, Jackson’s head lowered, his chin sinking into his chest. Afterward, he briefly shook hands with his attorneys before walking out of the courtroom flanked by Flathead County Detention Center personnel.   

News Editor Derrick Perkins can be reached at 758-4430 or [email protected].