Bigfork Man Sentenced to 100 Years for Murdering Mother’s Boyfriend

A 39-year-old man convicted of fatally shooting his mother’s boyfriend in their Bigfork home was sentenced Tuesday to 100 years in the Montana State Prison, a punishment the judge said accounts for the defendant’s lengthy criminal history, drug use, his risk of reoffending, and the unlikely self-defense case he mounted during a double-homicide trial earlier this year.

A Flathead County jury in April found Derrick James Jackson guilty of a felony count of deliberate homicide in the death of Stanley Grotberg, 65; however, the jurors found him not guilty of murdering his 62-year-old mother, Tricia DeMotts, who died at the scene of a fatal gunshot wound. The jury also convicted Jackson of a felony count of tampering with or fabricating evidence.

In October of 2022, Jackson – who maintained that he did not shoot DeMotts and acted in self-defense – fatally shot his mother’s boyfriend after an altercation between the defendant and Grotberg in their Esteban Lane residence in Bigfork.

On the day of the shooting, Jackson and Grotberg got into a physical fight in the kitchen of the home they shared after Grotberg became verbally abusive toward DeMotts. At that point, prosecutors say Jackson shot them both twice in the bedroom. However, Jackson denied shooting his mother and instead blamed Grotberg for her death, a narrative he maintained throughout the trial, including in testimony that he shot Grotberg in self-defense while cradling his mother’s body.

Flathead County District Court Judge Amy Eddy imposed the punishment at a June 17 hearing, delivering an 80-year sentence in the Montana State Prison for a single count of deliberate homicide; a 10-year sentence on the felony count of tampering or fabricating physical evidence; and a 10-year sentence for use of a firearm. The sentences will run consecutively, for a net sentence of 100 years. He was also designated as a persistent felony offender.

Judge Eddy cited a variety of factors that contributed to her sentencing decision, including the defendant’s record of substance abuse, his poor behavior in jail, the threat he poses to public safety, and his failure to maintain sobriety and remain law-abiding following the completion of numerous rehabilitation programs.

The judge also took the defendant’s lengthy criminal history into consideration, including his seven prior misdemeanor convictions, four prior felony convictions and eight prior revocation proceedings, which were described at length by Scott Brotnov of the Montana Department of Corrections Probation and Parole Office during testimony. The offenses, which date back 20 years, included several burglaries, partner or family member assault, DUIs and criminal possession of dangerous drugs.

“Risk assessments list him as high,” Brotnov said.

“It’s more likely than not that he’s going to continue his criminal behavior,” he added.

In 2016, Jackson escaped from the Cascade County Detention Center and, on a separate occasion, walked away from the pre-release center in Great Falls only to be arrested in Kalispell 100 days later.

“When the defendant was released back into the community in May of 2022, the conditional release status was only made possible because Mr. Grotberg and Ms. DeMotts agreed that the defendant could live with them and provide the housing for him,” Eddy said. “Nonetheless, the defendant continued to use methamphetamine through that period. This crime occurred 10 days after the defendant was released from jail.

In her sentence, Judge Eddy also cited the defendant’s multiple failed attempts at rehabilitation through the Montana Department of Corrections and the NEXUS substance abuse program in Lewistown, along with a pre-release program in Great Falls.

Eddy said that just because the jury acquitted Jackson in the death of his mother doesn’t mean they believed his defense. She described their decision as “incredulous” about Jackson’s claim at trial that he cradled his mother’s body following the shooting – despite the absence of her blood on him.

Prior to the trial, Jackson received a mental health evaluation from the Montana State Hospital, which reported he did not have a mental disease but that he exaggerated symptoms like fainting to avoid accountability.

“The defendant is a demonstrated threat to the community, and it’s in the best interest of the community for him to be incarcerated for a significant length of time,” Eddy said. “He has previously exhausted most treatment options through the Department of Corrections.”

Judge Eddy did not follow the sentencing recommendations of Deputy Flathead County Attorneys Amy Kennison and Katie Handley, who recommended a net sentence of 120 years. Kennison asked the court to consider Jackson’s criminal record and his behavior at the Montana State Hospital and the Flathead County Detention Center, which included falsifying medical symptoms and listed five disciplinary actions at the jail.

“As far as his criminal history, it’s a very extensive criminal history,” Kennison said.

While Jackson’s defense attorney Levi Roadman acknowledged the defendant’s criminal record, he stood by his client’s innocence in the death of his mother and blamed his battle with substance abuse for the tragedy. He recommended a 20-year sentence in the Montana State Prison with 10 years suspended.

“I do think that Mr. Jackson could be rehabilitated,” Roadman said.

Jackson’s father, John Jackson, during testimony at Tuesday’s hearing described a series of events that led up to the homicide on Oct. 28, 2022, which included tensions in the household on Esteban Lane.

“He wasn’t completely blameless – he did bring tension to the house,” John said.

John also said his son sustained a life-threatening head injury in the months leading up to the incident that involved a life-flight to Seattle and has since contributed to serious health problems and a change in his demeanor.

John said his son had expressed remorse over his responsibility in Grotberg’s death, but maintained he did not murder DeMotts.

“I believe 100% he did not shoot his mom – even though they argued at times, he loved his mom,” John said.

Grotberg’s son, Eric Grotberg, also testified during the sentencing hearing and described the trauma he and his family have experienced following his father’s death, which has left them distant from friends and has created issues for his kids at school.

“I believe because of the impact it’s had on our lives – and it will be for the rest of our lives – he should receive the maximum sentence,” Eric said.

Prior to sentencing, Jackson testified to the court and expressed remorse over Grotberg’s death, saying he “acted on a survival instinct” and feared for his life during the shooting.

“My actions in defending myself caused Stan’s death and that is truly a tragedy. Now his loved ones have to go through life without him,” Jackson said in tears. “For that, I’m so sorry. That is not what I wanted. I pray that the wounds in your hearts heal and that someday you will forgive me so you can have as much peace as possible.”

Following the apology, Jackson described a tense relationship with Grotberg, which resulted from disrespect toward his mother and said he had made threats to kill his father.

“I do not mean to bring this up to drag his name through the mud,” Jackson said. “I just want it to be clear.”

[email protected]