Community Police & Fire

Judge sentences man to more than 17 years in prison for 2020 murder of his neighbor

Posted on May 21st, 2024 By:

A Pierce County Superior Court judge on Monday sentenced Mark Allen Erisman, 61, to more than 17 years in prison for the Oct. 4, 2020, murder of Diane Perron at her home on Valley View Drive in Gig Harbor.

Erisman pleaded guilty under an agreement between Pierce County prosecutors and his public defender, Kelsey H. Page. Erisman was experiencing a mental health crisis at the time of the killing, and the trial was delayed repeatedly before doctors deemed him mentally competent to stand trial. 

The 61-year-old Gig Harbor man believed Perron, his 76-year-old neighbor, had set up devices to chase birds and other wildlife away from his property. Erisman, whom prosecutors wrote in court documents “lived a life of isolation,” viewed the birds and squirrels as family members. 

207-month sentence

Despite several previous contacts with law enforcement and mental health co-responders, Erisman broke into Perron’s home on Oct. 4, 2020, and shot her at least seven times.  

After reaching the plea agreement, prosecutors recommended that Judge Grant Blinn sentence Erisman to 207 months in prison. Page requested a 183-month sentence. Blinn went with the prosecutor’s recommendation, which amounts to 17 years and three months. 

In documents filed with the court, Pierce County Deputy Prosecutor Thomas D. Howe argued that Erisman’s mental illness “strongly influenced” his crime, but not enough to absolve him of responsibility.  

Supporting this argument were Erisman’s statements when he was arrested. He told police “You got me” and asked “Is she dead?” He told officers that his gun was in his car, indicating that he understood he had done something wrong.

An evaluation conducted in the weeks after police arrested Erisman found him incompetent to stand trial due to schizophrenia spectrum disorder. Doctors at Western State Hospital in Lakewood treated him for more than a year for what they described to the court as “schizoaffective disorder, bipolar type and unspecified substance-related disorder.”

‘The most important person in my life’

Victim statements submitted to the court by Perron’s survivors showed her to have been a kind, caring person who knitted hats for cancer patients, loved celebrating birthdays and served as a legal guardian for a person with developmental disabilities.

“My mom, Diane, was the most important person in my life,” wrote Perron’s daughter, Michele Bathurst. “She was my best friend. … She was full of love and life and had such immense energy to live life to the fullest.” 

“Diane was the purest soul that I have ever known, and I am fortunate to call her mom,” wrote Perron’s son, Ken Bathurst. “She was more that I could ever hope for in my life and she taught me how to be a good human being.” 

Michele Bathurst told Blinn in her victim statement that she hopes Erisman finds his end the same way her mother did.

“I hope that while Mr. Erisman is in prison that he suffers greatly,” she wrote. “I hope he dies on a cold prison floor, the same way my mother died — scared and alone.” 

Ongoing harassment 

According to Ken Bathurst’s statement, Erisman’s harassment of Perron went on for at least five years. Bathurst wrote that Erisman attempted to break into Perron’s house in 2016 and that he “held the neighborhood hostage with his unruly threatening behavior.”

Deputies and a mental health co-responder spoke with Erisman on the morning of Oct. 1, two days before he killed Perron. Neighbors had called 911 to report that he was walking up and down the road — not far from the intersection of Hunt Street and Lombard Drive — yelling that he intended to “blow his brains out,” according to court documents.

Erisman told the deputies and co-responder that he didn’t intend to harm himself. They gave Erisman information on how to contact a crisis line and how to get in touch with the co-responder, then left.

According to information submitted to the court by Page, the public defender, Erisman later contacted the crisis line but was not satisfied by its response. He made at least two attempts to reach the mental health co-responder — a MultiCare employee who responds alongside law enforcement when needed — but was unable to.

‘System was not there for him’

The co-responder told Page that only she and one other colleague worked swing shift, and at times they must “triage” requests for service.

“Mr. Erisman tried time and again to get help for his escalating mental health crisis,” defense attorney Page wrote. “The recommendations he did get, he followed to a word, but our public mental health system was not there for him when he most needed it. While this does not detract from his ultimate responsibility, it is important context when sentencing him for this offense, which was the climax of that crisis.”

Erisman himself said as much when he was arrested. Police found him walking on Ruston Way in Tacoma around 9 p.m. on the night of the murder. He had attempted to find refuge with a family member who lives in the area.

“I cried out for help so many times and no one helped me,” officers reported Erisman telling them. “I was yelling for help, but no one helped me.”

One such attempt was in the hours before the murder. Erisman called 911 at about 2 p.m. on Oct. 3 and reported that his neighbor’s electronic devices were scaring away wildlife.

Erisman told deputies he ‘snapped’

He told the dispatcher that he was going to “strangle” his neighbor, but he would prefer not to confront her himself. According to the public defender’s account, Erisman told dispatchers that “he wanted to kill the neighbor next door.”  He also repeatedly said versions of, “but that wouldn’t be right.”

Dispatchers notified the co-responder, who called Erisman at about 2:50 p.m. He again requested deputies. Though she told him, “It’s not my place to deny people deputies,” he misinterpreted her response to mean police would not respond.

They did respond, at about 3:15 p.m. But Erisman didn’t answer the door at his house, and they left the scene at 3:23 p.m.

Erisman’s nephew called 911 at 4:45 p.m. to report that Erisman told him he had killed a neighbor. A second person called 911 around 7:19 p.m. to report that Erisman told her the same.

Deputies checked Perron’s home at 7:40 p.m. and found her remains inside the home. Investigators later determined that Erisman shot out her surveillance camera before kicking in her door.

Erisman told deputies that he viewed the surveillance camera as a “frequency device” and an “electronic repellant device.” He also told them that he contemplated suicide earlier in the evening, before deciding against it.

He then “snapped,” armed himself and went to Perron’s home.