Whatcom County trial for Seattle man accused of murdering brother goes to jury
Jury deliberation began Friday after a two-week trial in Whatcom County Superior Court in the case of a Seattle man accused of shooting and killing his brother during a trip back from Republic in 2022.
John Roper Thomson, 42, reportedly killed his half-brother, 69-year-old Robert Thomson, near the western end of Diablo Lake in the North Cascades National Park on Aug. 8, 2022. He was charged with first-degree murder and two counts of unlawful possession of a firearm.
If jurors determine that John Thomson is not guilty of first-degree murder — which involves premeditation and intent to kill — they can potentially find him guilty of a lesser offense, such as second-degree murder, first-degree manslaughter or second-degree manslaughter.
In his closing argument Thursday, Eric Richey, Prosecuting Attorney for Whatcom County, said that each of the 20 rounds John Thomson fired at his brother “showed an intent to kill.” He repeatedly referenced a call that John made to his godmother from the Whatcom County Jail on Aug. 11, 2022. In the call, John relayed details about the crime. He said his brother was beating him, and that he “deserved it.”
“This was more than heat of the moment,” Richey said.
He said the call from jail was “diametrically opposed” to John’s testimony on the witness stand.
“John was accurate when he wanted to be,” Richey told jurors.
Starck Follis, director of the Whatcom County Public Defender’s Office, gave the closing argument in John’s defense. He said John had “no real motivation to kill Robert,” and that he was acting in self-defense because he believed Robert was going to pepper spray him.
John was on a mixture of drugs and alcohol at the time of the incident, Follis said, and likely didn’t even have the ability to come up with something like a plan to kill. He was “severely impaired,” and the remoteness and darkness at the time of the shooting would have made John even more scared for his life in the moment.
Follis represented John with Public Defender Matthew Mearns.
John Thomson’s testimony
John began his two days on the witness stand by describing his childhood in a “highly dysfunctional” family. He said he began using drugs and drinking alcohol in middle school. By the time he was 19, he was regularly consuming heroin, cocaine, Xanax and alcohol.
“It’s taken everything from me,” he said.
He was in active addiction at the time of the incident, and had initially planned to go to the cabin with his brother after he detoxed. Robert Thomson decided they should leave earlier for Republic, John said, and they departed Seattle on Aug. 5.
John said his brother gave him money to buy Xanax ahead of the trip to help with withdrawal. John also brought heroin and vodka with him.
The trip itself was planned after John’s neighbor said his cabin had been broken into. Robert stopped at his storage unit to get a generator and a chainsaw to use there. They spent the night in Puyallup, and then stopped to get more things from his storage unit. By the time they left for the cabin, it was about 5 p.m.
John said the trip to Republic was positive, though it took more than twice as long as usual. He said they stopped on the way to get food and gas and take care of John’s cats, which he’d brought with him. He said he didn’t know why the timing “doesn’t add up.”
When they arrived at the cabin, they found it had been broken into, and many of John’s belongings were missing. His guns were still there, as he’d hidden them inside the wall.
They slept for a few hours, but when John woke up, he realized he’d forgotten to pack his medication. He said he told his brother that he either needed to go back to Seattle or to a hospital, and Robert “flipped out.”
He said Robert started screaming and throwing things, which triggered his anxiety and PTSD. He tried to go to his neighbor’s house, but she wasn’t home. Robert wanted to leave the generator and chainsaw with the neighbor, but John told him not to.
He said his brother elbowed him in the face, though he ultimately agreed to pack everything into the car. John put his AR-15 and revolver in the car too, which he said Robert knew about.
The drive back
They stopped at a gas station in Tonasket, where John said he used heroin and Xanax. The Xanax hit him when they encountered police in Omak, and he doesn’t recall much of the interaction.
Jurors were shown body and dashboard camera footage from the contact with police. State Patrol had found the Acura on the side of the road with the brothers waving out the windows. Robert got out of the car to speak with officers, and John could be heard cursing at him from the passenger seat.
He eventually got out of the car, and he and his brother started shoving and yelling at each other. The responding officer called for backup and separated the two of them on opposite ends of the car.
John told police that he was thirsty and wanted to go home. At one point, he laid down on the asphalt with his head near oncoming traffic. He refused help from paramedics when they were called, and he and Robert eventually drove away.
“It seemed like anything I did set him off,” John said.
He recalled falling asleep in the car multiple times only to be woken up by his brother hitting him or slamming on the breaks. Robert also threatened to kill him and leave him behind on the side of the road, he said. Phone records show John tried to call 911 three times while they were driving through the North Cascades but did not have cell service.
John said past experiences made him more afraid of his brother hurting and threatening him. One time, he said, John slept overnight in his brother’s RV without permission. When he woke up, Robert shoved him and hit him with a baseball bat. Another time, he threatened John with a gun. Then, in 2021, while he, Robert and a friend were driving to the cabin in Republic, Robert dragged his brother along the side of the highway by his seat belt.
Mile post 128
John Thomson said he woke up at about 4 a.m. Aug. 8, 2022 to find the car pulled over at mile post 128 on Highway 20. Robert was outside of the car, John said, and he heard him going through the trunk.
He said he thought his brother may be getting food for the cats; but when he didn’t hear the sound of food bags, he thought Robert could be taking out the revolver from John’s satchel. He said he’d stowed the bag in the trunk while they were stopped in Twisp so that Robert couldn’t easily access it.
At that time, he said his brother had pepper sprayed him multiple times. It was disorienting and painful, he said, and it “compounded” with the drugs, alcohol, dehydration and PTSD on the side of the road. He told jurors that he heard a clicking sound that he thought came from the revolver and, fearing for his life, took the AR-15 out of the car and shot Robert.
“Everything just kind of happened so quickly,” he said.
He said the next thing he knew, he was down the embankment with his brother on top of him. He said he doesn’t know how he got back to his car, and doesn’t remember driving to the trail head or parking lot where police found him.
Differing accounts
When John was cross-examined by Richey, who prosecuted the case along with Deputy Prosecuting Attorney Sophia Padgett, he was questioned about previous accounts of the night of Robert’s death that didn’t match with what he said on the stand.
John said he didn’t recall telling the Whatcom County Sheriff’s Office sergeant booking him into the jail that Robert “had it coming.” He also said he didn’t remember telling detectives that his brother was urinating on the side of the road when John shot him. He said on the witness stand that he didn’t doubt that he said these things, but that he was too intoxicated and in shock to actually recall them.
In an interview with Whatcom County Sheriff’s Office Det. Derrick Bogle after his arrest, John said he left his brother’s body on the hillside “to [expletive] rot.”
“He spurred me on, and I just couldn’t take it any more,” he told Bogle.
The contents of the interview were not brought up to be considered as facts in the case, but rather to call the credibility of John Thomson’s testimony into question.
This story was originally published May 3, 2025 at 9:36 AM.