A Massachusetts man is being held without bail in connection with a fatal stabbing Saturday inside Winchester Public Library.
Jeffrey Yao, 23, of Winchester, appeared in Woburn District Court Monday morning to face one count of armed assault with intent to murder and one count of murder.
His attorney, J.W. Carney, called Yao a troubled young man with a serious history of mental illness.
"It's been a very troubled existence. His mental illness has often been quite apparent and he's had a lot of contact with the Winchester police over the years," Carney said.
Middlesex District Attorney Marian Ryan said 22-year-old Deane Kenny Stryker, of Winchester, was sitting at a table at the library on Main Street at about 10:30 a.m. when Yao allegedly stabbed her from behind multiple times with a 10-inch hunting knife.
Yao slashed and stabbed her 20 times in the head and upper torso area, according to court documents.
Stryker was taken to a local hospital, where she was pronounced dead.
"My client's parents feel devastated about the death of that young woman who was totally blameless," Carney said in court.
Authorities said several people at the library tried to intervene, including a 77-year-old man who was stabbed in the arm. Ryan said that man is expected to survive.
Stryker was a first-year student at the University of New England College of Osteopathic Medicine.
UNE President James Herbert released a statement on Sunday, saying in part, "The University of New England community was shocked and saddened to learn of the death of one of our students, Deane 'Kenny' Stryker, who was killed on Saturday. We send our deepest condolences to Deane’s family and friends, who are facing an unthinkable tragedy."
Family friend Brad Harrington said Stryker was a "special kid."
"She decided early on that she wanted to be a doctor," Harrington said. "She’s overcome some, you know, real obstacles in her life."
NBC10 Boston learned from sources Sunday night that Stryker is the daughter of Dr. Timothy Stryker, who was questioned in the 1993 death of his girlfriend.
Neighbor Peter Luongo says Yao lived with his parents nearby for years but that he started behaving erratically last summer.
Neighbor Nicole Luongo said Yao had allegedly attempted to break into area homes and cause damage to property.
"I would sleep with a bat under my bed," said Nicole Luongo, who had gone to the police with concerns.
Authorities are investigating the possible motive for the stabbing.
Friends said Stryker and Yao both attended Winchester High School but it's unclear whether they knew one another.
Yao will return to court April 11.