Jackson acquitted of killing mom, guilty of murdering her boyfriend

A jury on Monday acquitted Derrick James Jackson of the October 2022 murder of his mother, but found him guilty of killing her boyfriend and unsuccessfully discarding the gun used in the Bigfork slayings.  

The jury returned with the verdict about 4 p.m., after roughly four hours of deliberation. Flathead County District Judge Amy Eddy, who presided over the weeklong trial, set sentencing for April 29.  

Deliberate homicide is punishable by between 10 and 100 years in Montana State Prison. Owing to the use of a gun in the crime, Jackson could face an additional two to 10 years behind bars. Tampering with evidence carries a maximum penalty of 10 years and a $50,000 fine.  

Jackson, wearing a gray suit and dark tie, briefly waved to his father before meeting with Flathead County Detention Center personnel.  

DETECTIVES INVESTIGATING the deaths began focusing on Jackson, 39, shortly after discovering the bodies of Tricia DeMotts, 62, and Stanley Grotberg, 65, during an Oct. 28, 2022 welfare check at their Esteban Lane home in Bigfork. Deputies had arrested Jackson earlier that day for allegedly trespassing on neighbors’ property. 

He was found wearing Grotberg’s hat and jacket and in possession of the older man’s prescription medication as well as a magazine for a firearm. The fully loaded .40-caliber Smith and Wesson used in the shooting was left discarded in nearby tall grass. 

Deputies performed the welfare check hours later after unsuccessfully trying to return Grotberg’s prescription medication. They spotted blood through the window of the family’s Esteban Lane home, according to court documents and witness testimony. 

In their closing arguments, Deputy County Attorneys Amy Kenison and Katie Handley said that all the available evidence pointed to Jackson as the couple’s killer. Jackson’s clothing tested positive for gunshot residue, and blood found on his jeans and sweatshirt matched Grotberg’s DNA. The only fingerprints found on the case containing the gun, stored inside Grotberg’s Nissan Pathfinder, belonged to Jackson.  

And he lied to law enforcement personnel about the blood on his hands, Grotberg’s health and whereabouts, and whether he lived with his mother on Esteban Lane, Handley told jurors. A deputy asked Jackson whether Grotberg was OK and Jackson had replied, “Should be,” she recounted. 

“[Grotberg] was lying in a pool of his own blood with two bullet holes in his head and parts of a bullet in his brain,” Handley said. “He was not OK.” 

Not once did he call 911, she said. Not once did he tell deputies or detectives or county jail personnel that his mother and her boyfriend were dead. 

“Think about the number of opportunities he had to ask for help,” Handley said. “He didn’t. He just told stories. He was punching trees, stomping around in the woods. He hadn’t been in his mom’s house in a while. All things that, according to the evidence in the case, are not accurate. 

DEFENSE ATTORNEY Thomas Schoenleben told jurors that the evidence provided by investigators during the dayslong trial matched Jackson’s retelling of the shooting.  

Jackson, who took the witness stand on Friday, testified that an angry Grotberg retrieved the gun from his Pathfinder and threatened DeMotts with the weapon in the family home. Jackson said he wrestled the gun away from Grotberg and hit him in the head with it before removing the magazine and tossing it to the floor.  

Grotberg, in Jackson’s retelling, grabbed the gun and headed for the bedroom with DeMotts following him. That’s when Jackson said he heard a gunshot. 

Investigating, he said he found his mother halfway off the bed, shot. His face twisting, Jackson described hopping onto the bed and cradling his mother before Grotberg pulled her off and fired a second round into her head.  

Jackson recalled again wrestling the gun away from Grotberg. And when Grotberg lunged at him, he said he pulled the trigger.  

Schoenleben said Monday that all prosecutors could prove was that Jackson had been in the vicinity of a gunshot, that he had at some point touched the gun case and that he had killed Grotberg, which Jackson admitted to under oath.  

As for Jackson’s behavior following the shooting, Schoenleben chalked it up to trauma. 

“Now think about that situation. He’s not a trained soldier; he’s not in the military. He’s not trained to endure these types of situations," Schoenleben said. “He just had to shoot and kill one man, which is traumatizing, after seeing his own mother get killed by [Grotberg]. That is a lot going on. It has to be extremely traumatic. It would have some effect.” 

He also returned to a familiar refrain for the defense, that detectives built their investigation around Jackson. They failed to look at any other explanation for what occurred on Esteban Lane that day, he argued, which included checking Grotberg’s clothes for DeMotts’ blood.  

“They already made up their mind,” he said. “They didn’t even bother to look for more evidence to unravel what was going on.” 

HANDLEY SOUGHT to preemptively blunt several of Schoenleben’s arguments, among them that a distraught Jackson had cradled his wounded mother.  

Investigators found DNA matching Grotberg on his bloodstained clothes, she said. They found none for DeMotts. 

She noted that the Smith and Wesson found with Jackson had a 15-round magazine in it and another round in the chamber. Jackson reloaded and then went traipsing around the neighborhood with the pistol stuck into his waistband, she said.  

Kenison, who prosecuted the case alongside Handley, reiterated Jackson’s failure to alert anyone to the shooting in her rebuttal. Did his actions afterward jibe with his assertion that he killed Grotberg in self-defense, she asked them.  

“He didn’t tell anyone, ‘Hey, go check on my mom. She got shot. She's face down in the bedroom,’” Kenison said.  

She also addressed the prosecution’s omission of any explanation for why the shooting occurred. Motive, she said, is not necessary to prove a defendant’s guilt.  

“You might want to know why but it's not something that has to be proven beyond a reasonable doubt,” she said. 

And Kenison quibbled with Schoenleben’s repeated assertion that the investigation had not gone far enough. More testing, review and analysis would have led back to the same conclusion, she said.  

“The state submits it would not show you anything they did not already have, that that defendant shot and killed both [Grotberg] and his mother,” Kenison said.  

News Editor Derrick Perkins can be reached at 758-4430 or dperkins@dailyinterlake.com.