Winchester man found not guilty in 2018 fatal stabbing

WOBURN, Mass. — Jeffrey Yao, the 27-year-old who admitted to fatally stabbing a medical student 20 times with a hunting knife and attacking another man who tried to stop his murderous rampage back in 2018, was found not guilty Wednesday due to a lack of criminal responsibility. Middlesex Superior Court Judge Kathe Tuttman civilly committed Yao to the Bridgewater State Hospital.

Yao had waived his right to a jury trial resulting bench trial.

Police confirmed back in February 2018, Yao walked into Winchester Public Library with a knife. He later stabbed 22-year-old Deane Stryker several times while she was studying for medical school. Stryler died from those injuries shortly after.

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During the case, Yao was evaluated for criminal responsibility by three experts. Each doctor found the defendant lacking criminal responsibility. They said he was incapable of seeing the wrongfulness of his conduct or the ability to conform his conduct to the requirements of the law.

Middlesex District Attorney Marian Ryan released a statement on the final results of the case, saying:

“The result in this case, which acknowledges the seriousness of the mental illness that this defendant is living with and was experiencing at the time of the murder of Deanne Stryker, was compelled by the findings of the medical experts. It does not alter our belief that Mr. Yao continues to pose a serious risk to the public and that his long-term civil commitment to Bridgewater State Hospital is required.”

—  Middlesex DA Marian Ryan

DA Ryan added that Stryker’s family requests privacy at this time.