Jury Convicts Bigfork Man of Murdering Mother’s Boyfriend in Double Homicide Trial
Derrick James Jackson, 39, was found guilty of one count of deliberate homicide and evidence tampering while he was found not guilty in the second count of deliberate homicide; the Flathead County jury delivered the verdicts on Monday afternoon
By Maggie Dresser
A Flathead County jury on Monday afternoon convicted 39-year-old Derrick James Jackson of one felony count of deliberate homicide in the October 2022 death of his mother’s boyfriend, 65-year-old Stanley Grotberg, but found him not guilty of murdering his 62-year-old mother, Tricia DeMotts. The jury also convicted Jackson of a felony count of tampering with or fabricating evidence.
Jurors delivered the verdict at about 4:30 p.m. following a six-day trial and more than four hours of deliberation. Jackson was remanded to the custody of the Flathead County Sheriff’s Office. A sentencing hearing is scheduled for April 29.
Judge Amy Eddy presided over the Flathead County District Court trial that began March 31.
Jackson and his attorneys appeared visibly relieved in response to the not guilty verdict pertaining to the defendant’s mother, while spectators in the courtroom gallery showed little emotion.
Closing arguments ended on Monday morning, with prosecutors Amy Kenison and Katie Handley maintaining that Jackson fatally shot DeMotts and Grotberg on Oct. 28, 2022, following an altercation between the defendant and his mother’s boyfriend in their Esteban Lane residence in Bigfork.
Throughout the trial, the prosecutors presented evidence and testimony that portrayed Jackson as the lone suspect, describing a timeline of events that began with the defendant exhibiting strange behavior in the days leading up to the shootings, including trespassing on multiple neighbors’ properties while under the influence of drugs and brandishing a pitchfork.
On Oct. 28, 2022, prosecutors say Jackson and Grotberg got into a physical altercation in the kitchen of the residence they shared after Grotberg became verbally abusive toward DeMotts. Jackson then shot them both twice in the bedroom, prosecutors alleged.
“Stanley and Tricia died in the exact same way – two bullets shot into each of their heads from the same gun,” Handley said.
During closing arguments, Handley reminded jurors of the evidence connecting Jackson to the crimes, which included Grotberg’s blood on his clothing, a firearm magazine in his pocket and his fingerprints on the gun case that held the murder weapon, a Smith & Wesson pistol he used in the shootings.
While Jackson admitted to shooting Grotberg in self-defense, he denied shooting DeMotts — a claim prosecutors said did not line up with evidence in the case. The defendant said Grotberg was the person who reloaded the gun, but prosecutors said his story was not credible and testimony ruled out that possibility due to the volume of bullets in the gun at the time it was recovered.
“The reload could not have happened before the shots were fired at Tricia and Stanley and there’s only one person who could have reloaded this gun – the one person who was in the home and still alive,” Handley said.
Following the shooting, Jackson removed Grotberg’s leather jacket and fedora from his dead body and put it on his own, walked over to the neighbor’s house and picked up a drill, prosecutors said.
After the neighbor called law enforcement to report him trespassing, Andy Westphal, a corporal with the Flathead County Sheriff’s Office, arrested him. Westphal testified that Jackson was being uncooperative at first, ditched his weapon, continued to exhibit strange behavior and did not mention the shooting. He also said he suspected he was under the influence of drugs.
“The manner of death, the forensic evidence, the defendant’s odd behavior after the fact – all of this is evidence of what happened on October 28, 2022,” Handley said.
Defense attorneys Levi Roadman and Thomas Schoenleben maintained throughout the trial that Jackson shot Grotberg in self-defense during an altercation and it was Grotberg who shot his mother. They also argued the investigation was incomplete and that Grotberg should have been identified as a suspect, particularly given the defendant’s statements that Grotberg had a history of abusing his mother.
While prosecutors dismissed Jackson’s credibility, Schoenleben said the defendant’s testimony lined up with the evidence and, since Grotberg’s DNA was never tested, there’s no proof that Jackson was the only shooter.
“Everything that Jackson has testified to matches the evidence that the state provided – that is that Stanley was arguing with his mom, he went out to get the gun … He also testified that Stanley was abusive toward his mother,” Schoenleben said.
Jackson’s attorneys also defended his strange behavior following the incident as a reaction to trauma and described him as an “odd guy.”
“What we have is a mountain of reasonable doubt,” Schoenleben said. “We have an incomplete investigation … what we have is zero – and I mean zero – forensic evidence to show Derrick committed these offenses.”