The chief of a Massachusetts police department that’s been gripped by allegations of sexual misconduct and murder told “Dateline” that she felt “obligated” to share details unearthed by her investigators in the harrowing case of Sandra Birchmore, who authorities say endured years of abuse in a police youth program before her death at the hands of a former detective.
In her first media interview, Stoughton Police Chief Donna McNamara offered an apology and said she hopes Matthew Farwell, the ex-detective accused of sexually exploiting the one-time police “explorer” before allegedly strangling her and staging her death to look like a suicide, is held accountable and sent to prison if convicted.
Two other ex-Stoughton officers — a former deputy chief and Matthew Farwell’s twin, William Farwell — were also accused of having inappropriate relationships with Birchmore, who’d long admired law enforcement and was 23 and newly pregnant when she died Feb. 1, 2021.
“I am sorry that she was treated so horrifically by three men from my department,” McNamara told “Dateline.” “She didn’t deserve that.”
“They dehumanized her,” she added. “It’s vile.”
For more, tune into “The Betrayal of Sandra Birchmore” on “Dateline” at 10/9 tonight.
Matthew Farwell, 39, was indicted in Massachusetts federal court last year on one count of killing a witness or victim and has pleaded not guilty. No trial date has been set. His attorneys declined to comment, but a previous lawyer urged people to “keep an open mind” and said that what is released publicly “is not necessarily the full story.”
The other two former officers, William Farwell and Robert Devine, have not been accused of any crimes. All three resigned during an internal affairs investigation into what McNamara described in 2022 as a “sustained and deliberate combination of lies, deceit and treachery” that violated her department’s policies.
The chief recommended that all three be “decertified” so that they can never again serve in law enforcement in Massachusetts.
The twin brothers entered voluntary decertification agreements last year. William Farwell told authorities that he was with Birchmore sexually a few times in 2020, according to a summary of the interview in a state police report. McNamara said there was no evidence they had sex when she was a minor. His attorney declined to comment.
Devine has denied the allegations and is fighting decertification. His lawyer declined to comment. At a decertification hearing earlier this year, Devine’s attorney called the case against him a “big lie,” according to The Boston Globe.
Death ruled a suicide
Birchmore was found dead on the morning of Feb. 4 after she failed to show up for work at the elementary school where she was a teacher’s assistant in suburban Boston. Her body was discovered in her apartment’s bedroom with the strap of a duffle bag wrapped around her neck, according to a detention memo in the federal case. A local police report shows that authorities believed she’d hung herself — a position supported by the Massachusetts Office of the Chief Medical Examiner, which concluded three months later that she died by suicide.
Birchmore’s family wasn’t convinced, however. A cousin who learned that she’d been seeing Matthew Farwell — a married father who’d been an instructor in the police explorer program that Birchmore participated in as a minor — disclosed those details to the state trooper investigating Birchmore’s death for the Norfolk County District Attorney’s Office.
In an interview with state police, Matthew Farwell acknowledged having sex with Birchmore, but he said the affair started when she was 22 and lasted less than a year, a police report shows.
McNamara, who had been chief since 2016, had worked with Matthew Farwell for more than a decade. The detective and firearms instructor was chatty and good at his job, McNamara recalled, and she said she’d seen “no major red flags” since the department hired him in 2012.
But the chief said she grew “very concerned” when she learned that Matthew Farwell had been having sex with a person whom she described as an “impressionable young lady” who’d started in the explorers program when she was young. McNamara placed him on administrative leave and launched an internal investigation that sorted through tens of thousands of messages shared by state police.
The picture that emerged was horrific, McNamara said.
Birchmore’s relationship with the detective
A team of investigators learned that his relationship with Birchmore allegedly started when she was a minor, McNamara said. According to the federal detention memo, she was 15 and he was 27.
McNamara’s investigators learned that Matthew Farwell allegedly had sex with her while he was on duty, she said. They also uncovered extensive messages between Birchmore and Matthew Farwell’s twin, William Farwell, that showed him asking her to take photos and videos of herself, McNamara said.
“It was pretty sick,” she said.
Investigators dug up Facebook messages between Birchmore and a person using the name “Marty Riggs” — a possible reference to Mel Gibson’s character in the buddy cop franchise, “Lethal Weapon” — that showed the person discussing meeting Birchmore for sex, McNamara said. Authorities believe that person was actually Devine, who ran Stoughton’s police explorer program for more than a decade, the chief said.
Devine told authorities that he never spoke with Birchmore on social media and said his Facebook account was hacked. McNamara said there was no indication that Birchmore was a minor at the time of her alleged exchanges with Devine.
McNamara said she had no clue about the apparent web of inappropriate relationships between Birchmore and officers in her department. But in September 2022, after a year-and-half long investigation, McNamara released the redacted findings of the probe and held a news conference where she tore into the twin brothers and Devine, whom she accused of manipulating Birchmore “right up until her final days.”
McNamara said she was seeking the permanent revocation of their law enforcement credentials.
The revelations left people alarmed, recalled Michele McPhee, a journalist who has covered the case for Boston Magazine.
“We’re talking about police officials who were supposed to be protecting this young woman, but instead did quite the opposite,” she told “Dateline,” adding that she credited the chief for “denouncing” her officers’ behavior. “It was a bold move to commission the report and to not brush it under the rug at all.”
Although the department’s internal inquiry was not a death investigation, McNamara said she had come to believe that Birchmore’s death was likely not a suicide and that Matthew Farwell was probably responsible for killing her. But the state police investigation did not result in criminal charges against Matthew Farwell. Birchmore’s cousin, Angelique Pirozzi, said the state police investigator repeatedly told her there was no evidence to show that he killed Birchmore.
“They were hanging their hat on the ME’s report,” she told “Dateline.” “It was a suicide.”
The Massachusetts State Police declined an interview request. The Norfolk County District Attorney’s Office, which oversaw the state police probe, said in a statement that it spent “substantial time and effort investigating, interviewing and analyzing evidence in the tragic death of Sandra Birchmore.”
In a statement, the medical examiner’s office said that it continued to stand by its ruling that Birchmore’s death was a suicide — a conclusion “based on the evidence available at the time of determination.”
Charged with murder
In the aftermath of McNamara’s news conference, she said that federal authorities reached out for information about the case. Her department provided whatever they asked for, she said.
Her department was also sued by Birchmore’s estate. A lawsuit accused the three officers of wrongful death and the department of negligent hiring and supervision. McNamara said she had expected the litigation, which remains ongoing, and declined to comment further.
Then, in August 2024, Massachusetts’ top federal prosecutor announced that officials were charging Matthew Farwell with killing Birchmore in an indictment that accuses him of grooming her, sexually exploiting her, strangling her and staging her death to look like a suicide. Prosecutors accused him of doing this after she said that she was pregnant with his child.
In his interview with state police, Matthew Farwell denied that he was the father and suggested that Birchmore was sleeping with multiple people. He acknowledged stopping by her apartment Feb. 1 to end their relationship, according to a police report that summarizes the interview, but said he left after an argument. (According to three sources familiar with the investigation, DNA testing has shown that he was not the father.)
Matthew Farwell had responded “poorly” to news of the pregnancy, according to the detention memo, which was authored by an FBI agent and notes that Birchmore told friends that he physically assaulted her.
Included in the 45-page memo was a disturbing detail about the timeline of the killing that could bring more scrutiny on the Stoughton Police Department. According to the document, on Jan. 20, 2021 — just days before Birchmore’s death — a friend of hers called the department and reported Matthew Farwell’s “sexual contact” with Birchmore to an employee.
The employee then told Matthew Farwell about the call, the memo states, prompting the detective to “angrily demand that the employee never tell anyone about the information.”
McNamara said she was aware of the call but declined to discuss the content of the conversation because it is under investigation.
Asked if it was a possible catalyst in the chain of events that led to Birchmore’s death, she said: “I believe it was.”
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