Crime

He was accused of stabbing a man to death in Tacoma. Here’s why he won’t go to trial

Tacoma police investigated a fatal stabbing in the 7000 block of Pacific Avenue in Sunday, Aug. 8, 2021.
Tacoma police investigated a fatal stabbing in the 7000 block of Pacific Avenue in Sunday, Aug. 8, 2021. Tacoma Police Department

A 54-year-old man accused of stabbing to death another man in a Tacoma grocery store parking lot over a purported drug deal gone bad has been declared mentally incompetent to stand trial.

Shawn Shelby Teeter was found unfit last month to understand the proceedings against him and assist in his own defense after Pierce County prosecutors charged him with two counts of second-degree murder in August 2021, court records show. As a result, charges against Teeter were dropped.

Teeter was accused of delivering a single, fatal stab wound to the chest of Aaron Mathiason, 46, who was found in a parking lot in the 7200 block of Pacific Avenue on Aug. 8, 2021. Mathiason was taken to Tacoma General Hospital, where he died during surgery.

Teeter and the victim had known each other and Teeter was upset because he believed that Mathiason had sold him bad drugs, according to authorities, who cited friends of the victim in charging papers.

Following a psychiatric evaluation, the case against Teeter was dismissed without prejudice on Nov. 9, meaning that prosecutors could bring back charges in the future, court records show. Teeter, who had previously undergone two other psychiatric evaluations and three separate efforts to restore his mental competency, is ineligible by Washington statute for further rounds of treatment intended to make him fit for trial.

He was ordered committed into a state hospital, where he was already being held, according to court records.

Under state law, there is no limit on how long a defendant can be involuntarily committed. Psychiatric evaluators might petition the court to keep a defendant against their will in successive 180-day increments, with new court hearings required after each period.

The News Tribune previously reported that Teeter had a prior criminal record and was convicted of first-degree manslaughter in connection with a fatal stabbing in 1994.

Shea Johnson
The News Tribune
Shea Johnson is an investigative reporter who joined The News Tribune in 2022. He covers broad subject matters, including civil courts. His work was recognized in 2023 and 2024 by the Society of Professional Journalists Western Washington Chapter. He previously covered city and county governments in Las Vegas and Southern California. He received his bachelor’s degree from Cal State San Bernardino. Support my work with a digital subscription
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