WOBURN (WBZ-AM) -- The man police say stabbed a young woman to death in the Winchester Public Library Saturday was arraigned Monday morning in Woburn District Court.
Jeffrey Yao, 23, is charged with murder and attempted murder. He pleaded not guilty, and was ordered held without bail.
Winchester Police said Yao snuck up on and fatally attacked 22-year-old Deane Stryker with a 10-inch hunting knife while she studied in the library's reading room--and injured a man in his 70s who tried to stop him.
There was still no information about a motive, or if the victim and accused killer knew one another. Both Yao and Stryker graduated from Winchester High School earlier this decade.
Police said Yao was known to them prior to the attack, and prosecutors noted that Yao had been in and out of mental hospitals.
After the arraignment, defense attorney J. W. Carney called the situation a nightmare for both families.
"It's the nightmare for the victim's family and my client's family is devastated that, after years of dealing with his mental illness, he commits this act," he said.
Carney said he's assembling a team of doctors for the defense. He hopes to have Yao declared not guilty for reason of insanity and committed to a maximum-security mental facility--perhaps for the rest of his life.
WBZ NewsRadio 1030's Kendall Buhl reports