Former detective Matthew Farwell is accused of strangling pregnant woman and trying to make death look like suicide

A former Massachusetts police detective accused of strangling a woman shortly after she told him she was pregnant with his child and then staging the crime scene to make it look like 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 molesting and abusing her as a teenager at the Stoughton Police Explorers Academy. Farwell was an instructor in the program designed to promote interest in police work and worked for the Stoughton Police Department from 2012 to 2022.

Farwell, 38, began having sexual intercourse with Birchmore at age 15, including while on duty, acting U.S. Attorney Joshua Levy said at a news conference Wednesday.

She “survived years of sexual harassment, 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 sexual abuse of minors, Levy said.

Prosecutors said Farwell killed Birchmore, 23, in her Canton, Massachusetts, apartment on Feb. 1, 2021, when he could no longer control her and when it became known that he had been having sex with her for years.

“He allegedly silenced them permanently,” Levy said.

Authorities initially ruled Birchmore's death a suicide.

Farwell was charged with 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 to impregnate her if she would remain silent about his past behavior and their relationship, according to a motion filed by prosecutors arguing for Farwell's pretrial detention.

Birchmore wanted to have a child and was looking forward to the pregnancy, but Farwell did not, and his behavior became increasingly erratic and dangerous, Levy said.

Birchmore told Farwell that the child was his and asked about doctor's appointments, ultrasounds and what information would be on the birth certificate.

“Losing control”

A month before Birchmore's murder, one of her friends contacted Stoughton police and told them Farwell had had sex with Birchmore, the indictment says.

“Mr. Farwell lost control in late 2020 and early 2021, and the information Sandra Birchmore possessed about his illegal conduct threatened to leak out. In fact, rumors about their relationship began to leak out less than two weeks before she was found dead,” Levy said.

After the friend came forward, the 6-foot-4 Farwell allegedly became violent toward the 4-foot-6 Birchmore, shoving her and putting her in a chokehold, Levy said.

Prosecutors said Farwell killed Birchmore just hours before the birth of their third child. Birchmore was strangled as a snowstorm approached the Boston area. Prosecutors said this served as an excuse for Farwell to keep Birchmore away from work for days.

Farwell concealed evidence related to Birchmore's death, the indictment says. For example, she told her to delete all evidence from her phone that the two had sex before she was 16. She also repositioned her lifeless body and staged her apartment to make it look like it was a suicide, the indictment says.

He also lied to investigators with the Massachusetts State Police, the agency that originally investigated Birchmore's death, by telling investigators his sexual relationship with Birchmore began in 2020, not seven years earlier, and by saying he had only had sex with her a few times, prosecutors said. He also allowed only “limited consent” to search his cellphone, the arrest motion states.

Disturbing allegations

Birchmore's alleged sexual abuse as part of the Police Explorers Club was the subject of an investigation by the Marshall Project, published in May in partnership with NBC News, that looked at allegations of abuse in police Explorer positions across the country. The program, launched by the Boy Scouts of America, aims to introduce teenagers and young adults to the work of police officers.