An alleged attack on a female staff member at a Department of Youth Services facility by accused teen murderer Philip Chism bears a chilling resemblance to the murder of a Danvers High School teacher, sources told Team 5 Investigates Karen Anderson. 
 
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 A spokesman for the Essex County Sheriff said that Chism, 15, assaulted the woman at the Dorchester DYS facility Monday. 
 
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 Surveillance video captured Chism following the DYS employee into a locker room carrying an object that appeared to be a pencil. 
 
 He then allegedly began choking her, and as she started to scream he began to punch her, Anderson reported. 
 
 According to Anderson's report, within seconds staff members rushed in to help her and were able to quickly pull Chism off. 
 
 Authorities said Chism, then 14, killed Danvers teacher Colleen Ritzer, 24, with a box cutter he had taken to school after she asked him to stay after for help. He allegedly followed her into the school bathroom, where she was murdered and raped. 
 
 Chism has pleaded not guilty to charges of rape, robbery and murder. 
 
 "The Department of Youth Services is working closely with law enforcement to investigate an assault that took place on a member of the staff at our Dorchester facility," said Alec Loftus, DYS spokesman, declining for privacy reasons to identify Chism. 
 
 Chism was taken to Boston Medical Center for a mental health evaluation. ||||| A woman working for the Department of Youth Services was allegedly attacked at the agency’s Dorchester facility on Monday by Philip D. Chism, the teenager accused of murdering a Danvers High School teacher in October. 
 
 “The Department of Youth Services is working closely with law enforcement to investigate an assault that took place on a member of the staff at our Dorchester facility,” the agency said in a statement released by its parent agency, the Executive Office of Health and Human Services. 
 
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 The statement did not identify Chism, of Danvers. But a spokesman for Essex County Sheriff Frank G. Cousins Jr. told the Globe that Chism is under investigation for allegedly attacking a DYS staff member. 
 
 Following the assault, Chism was transferred to Boston Medical Center for treatment of an unspecified medical issue, said Maurice Pratt, assistant superintendent for the sheriff’s office. 
 
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 “The Essex County sheriff’s office has a security detail assigned to him,’’ Pratt said. “The incident is being investigated by the Massachusetts State Police.’’ 
 
 Chism, 15, is charged as an adult in Essex Superior Court with first-degree murder and two counts of aggravated rape for the Oct. 22, 2013, killing of Colleen Ritzer, a popular, young math teacher at Danvers High. Chism has pleaded not guilty and is being held without bail. Because of his age, DYS had custody of Chism on behalf of the sheriff’s office. 
 
 Chism, who was 14 at the time of the attack, allegedly followed Ritzer into a bathroom at the school shortly before 3 p.m., slashed her throat, partially stripped her, and stole her cellphone, credit cards, and two driver’s licenses. 
 
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 He then allegedly took her body in a recycling bin to a wooded area behind the school, authorities have said. Chism allegedly raped Ritzer twice, once with an object. 
 
 A spokesman for Suffolk District Attorney Daniel F. Conley also said Tuesday that State Police detectives were investigating an attack Monday at the DYS facility in Dorchester. 
 
 “That investigation remains very active today,’’ Conley spokesman Jake Wark said, adding that no charges have been filed. 
 
 The statement issued by DYS did not disclose the extent of injuries suffered by the woman during the attack. But Wark said the victim, a woman in her 20s, declined medical treatment at the time of the attack. 
 
 “The safety and well-being of our staff is of primary concern and a full review of this incident will be conducted to identify any necessary security enhancements at the facility,’’ DYS said in its statement. 
 
 Previous coverage: 
 
 • Timeline of the murder of Colleen Ritzer at Danvers High School 
 
 • Lawyers for Danvers teen want charges dismissed 
 
 • For Danvers High, a new beginning 
 
 • Chism hit with new rape charge in teacher’s death 
 
 • Grisly new details released in murder of Danvers teacher
– The 15-year-old Massachusetts boy accused of raping and murdering his math teacher last year allegedly attacked a female staffer at his youth-detention facility, police say. The woman is apparently OK and declined medical treatment at the scene, while Philip Chism has been taken to a hospital for an evaluation, reports the Boston Globe. Authorities aren't saying exactly what happened, but WCVB-TV reports that Chism can be seen on surveillance video carrying what appears to be a pencil and following the woman into a locker room. After he began choking the woman, other staffers quickly pulled him away, reports the TV station, which points out that the scenario "bears a chilling resemblance" to how teacher Colleen Ritzer was murdered at Danvers High School last year. Chism is accused of following her into a school bathroom and killing her. He has pleaded not guilty in that case and is still awaiting trial.