A federal jury in Boston on Tuesday convicted Matthew Farwell, a 41-year-old former Stoughton police detective, of killing 23-year-old Sandra Birchmore and of causing the death of the fetus she was carrying. As the Boston Globe reported, the two convictions carry an automatic life sentence. He stays in federal custody until sentencing, which is set for Feb. 3.
“Today, justice was served for Ms. Sandra Birchmore and her unborn son,” US Attorney Leah B. Foley told a press conference shortly after the verdict. Ray Cosgrove, a cousin of Birchmore’s who spoke for the family, kept the focus on her: “Sandra mattered before anyone outside her family knew her name. Her life still continues to matter today.”
Prosecutors said Farwell strangled Birchmore in her Canton apartment on Feb. 1, 2021, and arranged the scene so it would look as if she had hanged herself. The defense said she took her own life that night, after he ended their relationship. The jury sided with the government.
Why a murder case ended up in federal court
The legal structure of this case is unusual, and it explains a lot about how the trial unfolded. Most homicides are state crimes. There is no general federal law against murdering someone in a Massachusetts apartment. Local prosecutors never charged anyone with Birchmore’s death, so federal prosecutors had to find a federal hook, and they used 18 U.S.C. § 1512. That statute covers anyone who kills another person with the intent to prevent that person from communicating information about “the commission or possible commission of a Federal offense” to federal law enforcement. A killing under that provision is punished under the federal murder statute.
That gave the government a lot to prove. It had to show that Farwell killed Birchmore and meant to. It also had to show his reason: that he did it to keep evidence of federal crimes away from federal authorities. Prosecutors named three such crimes. One was sexually exploiting Birchmore while she was a minor. The second was using his position as a police officer to violate her rights. The third was defrauding the Stoughton Police Department by having sex with her while he was on duty. Farwell was never charged with any of the three. The jury still had to be convinced that there was evidence tying him to each of them, and that silencing her about them was why she died.
So the abuse was doing two jobs at the trial. It was the motive, and it was also the jurisdictional basis for the case. That is why the testimony moved back and forth between the death scene, competing experts on the science of hanging versus strangulation, and evidence that Farwell had groomed Birchmore. In federal court, all of that was one argument. Earlier coverage set out that central question and the medical evidence behind it.
According to the New York Post, Birchmore met Farwell when she was 12, in the Stoughton police “Explorers” program for kids, where he was an instructor. She wanted to become a police officer. They first had sex in April 2013, when she was 15 and he was 27. The age of consent in Massachusetts is 16, and prosecutors called it statutory rape, made worse by the age gap and by his status as a police officer and mandated reporter. In closing, prosecutor Brian Fogerty told the jury: “According to the defendant, this was the best day of his life. Sexually abusing a 15-year-old girl was this man’s single best day.”
The relationship lasted until her death. Prosecutors said that as Birchmore got older she came to understand the leverage she had. She threatened to tell his wife, and told friends she had the upper hand because of how young she had been. What she wanted was a baby, and prosecutors said Farwell agreed to try to get her pregnant. She became pregnant at the end of 2020 and was sure he was the father. Testing after her death showed another man was. Prosecutors said Farwell was upset when she told him, and furious once a friend of hers called the Stoughton police dispatch line to report an affair. Dispatcher James Fitton testified that when he passed on the call, Farwell told him to “never talk about this again.” Prosecutors said Farwell decided to kill her after that call, 13 days before her death.
She died as a storm was coming in, the day before Farwell’s wife was due to give birth. Forensic experts testified that Birchmore’s phone, which the jury heard she always had with her, last recorded movement three minutes before surveillance video showed Farwell leaving her building. Defense attorney Kimberly Stevens told jurors that “Ms. Birchmore built a fantasy world around the idea … that she would be married to Matthew and have his kids.”
The jury of eight men and four women heard from 50 witnesses. At one point it sent a note saying it was deadlocked, and the judge told it the next morning to keep deliberating. The Globe put total deliberations at more than 15 hours over three days, while the Post said roughly 14. When the judge questioned each juror individually, every one said they found him guilty beyond a reasonable doubt. Much of the case rested on Birchmore’s own texts to friends, family and clinicians. “Through the testimony of friends and experts, through thousands of text messages and photos, what happened to Sandra Birchmore is no longer Mr. Farwell’s secret,” Foley said.
The first investigation
For a long time no one was held responsible. The state medical examiner ruled the death a suicide, and the initial investigation, run under Norfolk District Attorney Michael W. Morrissey, produced no charges. The FBI opened its own inquiry more than two and a half years after Birchmore died. Its medical expert concluded she had been strangled, and Farwell was arrested in August 2024. In April the medical examiner’s office changed its finding to “undetermined.” At trial, the medical examiner testified that Morrissey’s detectives had not noted anything suspicious. The lead investigator, State Police Lieutenant John Fanning, was never called as a witness, but prosecutors repeatedly blamed his handling of the case for the original ruling. That left federal prosecutors attacking the work of the state investigation that had reached the opposite conclusion.
The State Police have declined to comment on how their investigation has been described. Morrissey, who did not run for reelection amid criticism of his handling of this and other cases, said in a statement that his office “recognizes the criticism it has received for its handling of this case” and had deferred to the medical examiner. Reporters asked Foley several times whether any related investigations were still open. She declined to discuss the state’s work and said: “The charges we brought were the ones we were able to charge.”
Barbara Wright, another cousin, said the verdict means Farwell “can never hurt another human being again,” and added: “But there are still other people that we need to hold accountable. People who enabled him. People who [looked] the other way.” Stoughton Police Chief Donna McNamara, who ordered the internal affairs investigation into Farwell after Birchmore died, said: “Sandra Birchmore received no justice during her life. Today justice is served.”
The Justice Department’s announcement called the killing “a calculated attempt to silence her.” The statute that convicted him exists to punish people who silence witnesses. The people Wright says looked the other way are a separate matter, and so far no one has charged them with anything.