Six years of Winchester police interactions with Jeffrey Yao

( 02/26/18 Woburn, MA) Jeffrey Yao appears with his lawyer, J.W. Carney, Jr. during his arraignment in Woburn District Court on murder charges and attempted murder after allegedly stabbing a woman to death and attempting to stab a man to death in the Winchester Public Library. (Faith Ninivaggi/POOL)
Faith Ninivaggi/Associated Press
Jeffrey Yao appeared during his arraignment on murder charges and attempted murder in Woburn District Court on Feb. 26.

Jeffrey Yao, the 23-year-old man who authorities allege stabbed a woman to death in the Winchester Public Library on February 24, was well-known to police before that day, according to police reports released on Wednesday.

Here’s a timeline of Winchester police’s interactions with Yao during the past six years:

■Feb. 13, 2012 Two students at Winchester High School were concerned with Yao’s Facebook posts. Yao had posted video of a manifesto linked to the Virginia Tech mass-shooter and another video of a shooting demonstration. Police described Yao’s “noticeable decline in personal hygiene.” A police officer noted “we needed documentation from a psychiatrist indicating Yao was psychologically fit to be in school.” Yao saw a child psychiatrist, who appeared to clear him to return to school, according to the police report.


■ Nov. 12, 2012 Police responding to a report of someone hearing glass breaking around 2 a.m. found Yao on Lynch Elementary School grounds, minutes after someone made the call to authorities. An officer said he was familiar with Yao, saying “my history and interaction with Yao is extensive.” Yao was patted down and then driven home by police. Yao told police he couldn’t sleep, so he “snuck out for a walk.”

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■Jan. 17, 2013 Police responded to the Lynch school at the request of the principal, who said that a 5th grade female student had reported an “Asian male” had stared at her for extended period of time while she walked to school on two different occasions earlier in the month. The student and the man did not communicate and no physical contact was made, according to police. The student picked out Yao from a photo array.

■Jan. 20, 2013 Police spoke to Yao about trespassing, “obscene language, and threatening mannerisms.” “Yao known to be a wanderer with mental issues,” police wrote.

■Jan. 21, 2013 A police officer contacted a Rensselaer Polytechnic Institute official who said Yao agreed to leave the school the previous fall at the request of the school following anti-social behavior and personal hygiene issues, including “urinating in plastic water bottles instead of getting out of bed to use the bathroom.”

■ Feb. 17, 2013 Yao admitted to police that he swore at a woman after she spoke to him. The woman told police that she and her husband were bringing in groceries when she noticed Yao standing in front of an elderly neighbor’s house staring at the residence. She asked Yao if she could help him, and he yelled at her. Police told Yao to try to refrain from swearing and yelling at people, according to the report.


■ March 4, 2013 Yao’s father went to police and asked for advice to help his son, whom he said had been experiencing mental health issues.

Police release 911 calls from Winchester library stabbing

■March 17, 2013 Police saw Yao walking slowly down a street shortly after 5:15 p.m., stopping at homes, and peering down driveways and into yards before walking through one front yard. Yao, according to the report, appeared “out of it.” An officer told him he can’t walk through people’s yards, and that he looked suspicious. Yao told police he was out for a walk.

■ Nov. 13, 2013 An officer said Yao was in need of an evaluation after he spoke with his parents, who were concerned for their son’s well-being. The father told police that he woke up around 1 a.m. on Nov. 13 to find Yao standing in a hallway of their home with a six-inch, stainless steel knife. Yao “fondled” the knife for at least five minutes, according to the report. One of his parents told police “it is impossible to communicate with Jeffrey and that confronting him would have been useless.” His family contacted McLean Hospital, hoping to get him admitted, but were told that hospital’s “intake policy required an ER evaluation or crisis team intervention.” Police took Yao to Winchester Hospital for evaluation.

■ Jan. 30, 2014 Police responded to a report that Yao had bullied a female college student through Facebook. The student had posted about her mother’s tragic death in a New Jersey car crash, and Yao, according to the police report, allegedly responded with unkind comments and photos of fatal car crashes.

■ March 20, 2014 A former friend of Yao told police that Yao had been disseminating screen shots of a private online conversation they had in 2011. The conversation pertained to someone’s father being unfaithful. Yao was sending screen shots of that conversation to people and used an anti-gay slur to describe his former friend. According to police, someone told authorities that Yao had two Facebook pages, one that was “normal” and another that featured disturbing images, including “what she described as women being raped.”


■April 1, 2014 Police responded to a CVS on Main street after a report of a verbal argument involving Yao and another man. Yao told police he had accidentally bumped into another shopper. Yao said he apologized, but added that the other customer started to yell and swear at him. Yao asked a clerk to call police, and the other man left the store. Yao told police he just wanted the incident documented, according to the police report.

■April 14, 2014 Yao reported that his bicycle was stolen outside a CVS. Days later, an officer saw Yao riding a bike that appeared to be the one he reported stolen. Yao told police he found the bike in a parking lot on Church Street.

■ May 30, 2014 Yao allegedly ran across a sports field while a lacrosse game was in progress. Police told Yao he had to leave school grounds or he would be arrested for trespassing.

■Feb. 24, 2016 A neighbor went to the police station to express her concern about Yao. He had broken her front door-window by throwing a shovel while she was away, she told police. The neighbor was aware that Yao “has some mental health issues” and was concerned because she has “young children who commonly play outside.”

■March 22, 2016 Yao called police and said he wanted to “turn himself in” because he had kicked in a door of his home. He told police he would be released from a mental health facility the following day and wanted to be arrested for kicking in the door. His mother told police there had been no damage to her home.

■Oct. 7, 2016 Police responded to Winchester Public Library after a health care worker reported that Yao had made suicidal statements. Yao agreed to go to Winchester Hospital for a mental health evaluation.

■ Dec. 7, 2016 Yao went to the police station and told an officer that his therapist was threatening him. Yao also told police he had commented on a Facebook post about someone who had committed suicide, by saying that he was glad the person died. According to the police report, he also told police that he had trouble breathing and that there were chemicals coming through vents in his home that were causing him to get sick.

■ June 28, 2017 Yao asked a customer at The Dairy Barn on Main Street if he would “do me a favor and kill me,” among other disconcerting statements. He was also reported to have been acting strangely in Andrea’s Pizza, where police found Yao. Yao asked an officer if he would kill him, according to the police report. Yao also told police he had “done something bad and needed to be punished,” and asked for help because “he was feeling schizophrenic.” Yao agreed to be taken to Winchester Hospital.

■ Feb. 7, 2018 Yao, driving on Lake Street, slid his vehicle into the rear of another vehicle on a slick, snowy road, according to a police report.

Danny McDonald can be reached at Follow him on Twitter @Danny__McDonald.