A former Massachusetts police detective accused of strangling a woman who had recently told him she was pregnant with his child and then staging the scene to appear as a suicide has been charged in her 2021 death, federal prosecutors said Wednesday.
They allege that Matthew Farwell killed Sandra Birchmore years after he began grooming and sexually abusing her as a youth in the Stoughton Police Explorers Academy. Farwell was an instructor in the program designed to foster an interest in police work and worked for the Stoughton Police Department from 2012 to 2022.
Farwell, 38, began having sex, including while on duty, with Birchmore when she was 15, Acting U.S. Attorney Joshua Levy said at a news conference Wednesday.
She “survived years of grooming, statutory rape and then sexual violence, all at the hands of Matthew Farwell," Levy said.
Farwell befriended her, contacted her online and went to the library with her before he began committing statutory rape, Levy said.
Prosecutors said Farwell killed Birchmore, 23, on Feb. 1, 2021, in her Canton, Massachusetts, apartment when he could no longer control her and as word began to get out that he had been having sex with her for years.
“He allegedly silenced her permanently,” Levy said.
Birchmore’s death was initially ruled a suicide by authorities.
Farwell has been charged with one count of killing a witness or victim. He was arrested by the FBI in Revere, Massachusetts, on Wednesday.
A lawyer for Farwell did not immediately respond to a request for comment.
In October 2020, Birchmore told Farwell she wanted to have a baby and he agreed to try and impregnate her if she stayed silent about his past behavior and their relationship, according to a motion prosecutors filed arguing for the pre-trial detention of Farwell.
Birchmore wanted to have a child and was excited about her pregnancy, but Farwell was not and his behavior grew more erratic and dangerous, Levy said.
Birchmore told Farwell the child was his and began asking him about doctors’ appointments, ultrasounds and what information would be on the birth certificate.
A month before Birchmore was killed, one of her friends contacted Stoughton police and told them Farwell had been having sex with Birchmore, the indictment said.
“Mr. Farwell was losing control in late 2020 early 2021 and the information that Sandra Birchmore possessed about his illegal conduct was in danger of slipping out. In fact, word started to get out about their relationship less than two weeks before she was found dead,” Levy said.
After the friend came forward, 6-foot-4 Farwell allegedly became violent with 4-foot-10 Birchmore. He pushed her and put her in a chokehold, Levy said.
Prosecutors said that Farwell killed Birchmore hours before his wife delivered their third child. Birchmore was strangled as a blizzard approached the Boston region, which prosecutors said would give Farwell cover for Birchmore's absence from work for days.
Farwell concealed evidence in Birchmore's death, according to prosecutors, by telling her to delete evidence on her phone that they had sex before she was 16; repositioning her lifeless body and staging her apartment to look like a suicide, the motion said.
He also lied to detectives with Massachusetts State Police, the agency that initially investigated Birchmore's death, by telling investigators his sexual relationship with Birchmore began in 2020, not seven years earlier, and by saying he only had sex with her a few times, prosecutors said. He also allowed only "limited consent" to search his cellphone, the detention motion said.
Birchmore's alleged sexual abuse as a part of the police Explorers club was included in a Marshall Project investigation, published in partnership with NBC News in May, about abuse allegations in law enforcement Explorer posts across the country. The program, created by the Boy Scouts of America, aims to teach teens and young adults about policing.
The news of Farwell's arrest comes two years after the chief of the Stoughton Police Department announced that Farwell and two other former officers at the agency, including Farwell's twin brother, William, had inappropriate relationships with Birchmore.
William Farwell has previously denied the allegations.
That conclusion came from a lengthy internal affairs investigation prompted by Birchmore's death, said the chief, Donna McNamara, who called the former officers' behavior "deeply disturbing."
“Through a sustained and deliberate combination of lies, deceit and treachery, they violated the policies and the core values of the Stoughton Police Department,” McNamara said at the time. "Not to mention human decency.”
McNamara said that the Farwell brothers began as youth participants in the Explorers club under Robert Devine, the third former officer accused of having an inappropriate relationship with Birchmore. Devine has denied the allegations.
Devine, a former deputy chief at the Stoughton Police Department, had transformed the Explorers program from a scouting club into a paramilitary group that taught aspects of policing to young people, McNamara said.
Like Matthew Farwell, William Farwell was also an instructor in the program in the town about 25 miles south of Boston, McNamara said.
Before Birchmore entered the Explorers club as a young teenager, she’d had a difficult childhood but developed a deep admiration for police, according to a wrongful death suit that her family filed against the Farwell brothers and Devine in 2022.
"People with oaths and duties to protect and serve led her to form relationships with men who were willing to take advantage of her," McNamara said.
When Matthew Farwell began his alleged sexual relationship with Birchmore when she was 15, McNamara said, he was 27.
The internal affairs investigation uncovered hundreds of messages and explicit exchanges between them that spanned years, McNamara said. The probe also showed that William Farwell introduced Birchmore to other men, she said.
McNamara said all three men resigned from the department before they could be interviewed.
Asked about the other former officers Wednesday, Levy would not comment.
The department recommended that their certifications as police officers be permanently revoked so they cannot serve in law enforcement anywhere in the country, McNamara said.
Lawyers for William Farwell and Devine did not immediately respond to requests for comment about the status of their decertifications.
In a statement Wednesday, McNamara said it had been her priority for the last three years to ensure justice in the case.
"Sandra Birchmore received no justice during her life," she said. "It is imperative that justice be served in her death, and today’s actions appear to bring our society one step closer to justice.”
