When the Police Protect and Serve Only Themselves: Sandra Birchmore and the Federal Trial of Matthew Farwell

By Attorney Joe Serpa | Georgetown University Law Center

This post is for general informational purposes only and is not legal advice. It is based on the superseding indictment, the public rulings of the United States District Court for the District of Massachusetts, the Stoughton Police Department’s public statements about its internal affairs investigation, and published news reporting on the trial. Matthew Farwell has pleaded not guilty and is presumed innocent. An indictment is an accusation and not evidence. William Farwell and Robert Devine have not been charged with any crime and have denied wrongdoing. Reading this post does not create an attorney-client relationship. This may constitute attorney advertising.

Sandra Birchmore was 23 years old and eight to ten weeks pregnant when she died in her apartment in Canton on February 1, 2021. She worked as an instructional assistant at a school. She had told her friends for years that she wanted to be a mother, and she had told the man she believed was the father that she was keeping the baby.

Police found her body three days later, on February 4, 2021, with a duffel bag strap around her neck tied to a closet door handle. The State Police detectives assigned to the Norfolk County District Attorney’s Office and the Office of the Chief Medical Examiner ruled her death a suicide.

Three and a half years later, on August 28, 2024, FBI agents arrested Matthew Farwell, a former Stoughton police detective, in Revere. A federal grand jury had charged him with killing Ms. Birchmore to keep her from reporting that he had been having sex with her since she was 15 years old.

His trial is now under way in the Moakley Federal Courthouse in Boston before Chief Judge Denise J. Casper of the United States District Court. The lawyers delivered their opening statements on October 9, 2026. Testimony began on October 13, and the trial is expected to last about five weeks.

Mr. Farwell has pleaded not guilty. His lawyer told the jury that he had an affair with Ms. Birchmore, that he made regrettable mistakes, and that she took her own life after he ended the relationship.

This is the first in a series of posts on the trial. It describes who Sandra Birchmore was, the three Stoughton police officers who, according to the department’s own investigation, had sexual relationships with her, the telephone call a friend made to the Stoughton police twelve days before she died, the investigation that closed her death as a suicide, the federal charges that reopened it, and what the jury must decide.

It is written from her side. Attorney Serpa’s view is that the men who were sworn to protect her failed her while she was alive, and that the investigators who were supposed to speak for her after her death failed her a second time.

Sandra Birchmore

Sandra Birchmore grew up in Stoughton and admired police officers from the time she was a child. She applied to join the Stoughton Police Explorers in March 2010, when she was 12 years old. The Explorers was a program the police department ran to teach local teenagers about careers in law enforcement. She stayed in the program until about 2016.

The officers who ran the program were her instructors and her mentors. A Stoughton police sergeant testified at the trial that she was impressionable and looked up to the police.

By 2020 she was living alone in an apartment in Canton and working as an instructional assistant at a school. Her friends testified that she talked constantly about wanting to be a mother. One friend called her phone her third hand because she was never without it.

Sandra spent Thanksgiving and Christmas of 2020 alone. She learned in December 2020 that she was pregnant. She believed that Mr. Farwell was the father, and she told him so. She was eight to ten weeks pregnant with a boy when she died.

The Three Stoughton Officers

Matthew Farwell was a volunteer with the Explorers before the Stoughton Police Department hired him in March 2012, and he became an instructor in the program when he joined the department.

In September 2022, after an 18-month internal affairs investigation, Stoughton Police Chief Donna McNamara announced that three officers of her department had sexual relationships with Ms. Birchmore. According to the department’s findings, Mr. Farwell’s sexual relationship with her began in 2013, when she was 15 and he was 27.

His twin brother, William Farwell, who was also a Stoughton officer, and Robert Devine, a former deputy chief who had run the Explorers program when the Farwell brothers were themselves teenage participants, had sexual relationships with her when she was an adult.

All three men resigned. Chief McNamara said that they had violated their oaths of office and should never again have the privilege of serving any community as police officers. She said the department’s investigation found that the three men misled the investigators who looked into Ms. Birchmore’s death.

She asked the Massachusetts Peace Officer Standards and Training Commission to decertify all three. Mr. Farwell has been decertified and is barred from police work in Massachusetts. The department shut down the Explorers program in 2022. Ms. Birchmore’s estate has sued Matthew Farwell, William Farwell and Robert Devine for wrongful death.

The federal grand jury’s allegations go further than the department’s findings. The superseding indictment alleges that Mr. Farwell had sexual intercourse and other sex acts with Ms. Birchmore before she turned 16 and continued until early 2021.

It alleges that he had sex with her during shifts when the Town of Stoughton was paying him to work as a police officer and that he concealed that conduct from the department. Prosecutors told the jury that investigators recovered about 40,000 messages between the two of them from her devices, and that the relationship was built on secrecy and control.

In Massachusetts, sexual intercourse with a child under 16 is rape of a child under G.L. c. 265, § 23. The child’s consent is not a defense. A person convicted under § 23 faces imprisonment in state prison for life or for any term of years. The Commonwealth may indict a person for rape of a child at any time after the offense. G.L. c. 277, § 63.

The Norfolk County District Attorney’s Office received the Stoughton Police Department’s findings in 2022. No Massachusetts prosecutor has charged Mr. Farwell with rape of a child or with any other crime.

The Pregnancy and the Call to the Stoughton Police

Ms. Birchmore told Mr. Farwell in December 2020 that she was pregnant and that he was the father. According to court papers filed by prosecutors, she told him that she was keeping the baby and that the birth certificate was going to be signed, and he answered that she was the worst person on the face of the earth.

Over the following weeks she sent him messages about her due date, her ultrasounds and her doctor’s appointments. A friend testified at the trial that Ms. Birchmore said Mr. Farwell shoved her to the ground when she asked whether he would sign the birth certificate, and that he refused because, he said, the child was not his.

On January 20, 2021, a friend of Ms. Birchmore’s called the Stoughton Police Department and told a department employee that Mr. Farwell had been having sex with her. The friend did the right thing. She reported the officer to his own department.

According to the indictment, a department employee then told Mr. Farwell about the call. Prosecutors told the jury that Mr. Farwell decided to kill Ms. Birchmore after he learned of the call. Twelve days later she was dead.

DNA testing after her death showed that Mr. Farwell was not the biological father of the child. The indictment does not allege that he was. It alleges that she told him he was. The federal charge depends on what he intended when he went to her apartment, not on the paternity of the child.

February 1, 2021

Mr. Farwell asked to visit Ms. Birchmore on the evening of February 1, 2021. Surveillance video from her building shows him walking into the lobby that evening and leaving about 30 minutes later.

Minutes before he left, her phone stopped moving. It stayed where it was until the battery died. Police found her body three days later. There was no suicide note.

The grand jury alleges that Mr. Farwell strangled her and then arranged her apartment to make her death look like a suicide. The defense says that he went there to end the relationship, told her the baby was not his, and left her alive.

The Investigation That Called Her Death a Suicide

State Police detectives assigned to the Norfolk County District Attorney’s Office and Canton police officers investigated the death. Trooper Matthew Dunne testified that he interviewed Mr. Farwell in a parking lot soon after the death and that Mr. Farwell admitted going to the apartment that night.

Mr. Farwell told investigators that the affair began when Ms. Birchmore was 22 and lasted less than a year. Trooper Dunne testified that he did not treat the death as suspicious. The Office of the Chief Medical Examiner ruled the manner of death a suicide.

In 2022 the Norfolk County District Attorney’s Office said that its investigation found no evidence of foul play. Chief McNamara testified that she first saw the lobby video of Mr. Farwell when it was published online.

The people who loved Ms. Birchmore never accepted the ruling. Her family said that she was not suicidal and never believed that she killed herself. A friend testified that she went to the police after the death and urged them to investigate Mr. Farwell. Chief McNamara said in 2022 that her department’s investigation was not a death investigation, but that she had come to believe Ms. Birchmore’s death was probably not a suicide and that Mr. Farwell was probably responsible.

Federal investigators took up the case in 2024. A medical expert consulted by federal prosecutors found that Ms. Birchmore’s injuries were not consistent with suicide. In April 2026 the Office of the Chief Medical Examiner withdrew its suicide finding and changed the manner of death to undetermined.

Why the Case Is in Federal Court

The Norfolk County District Attorney’s Office prosecutes murder in Norfolk County. The office presents the case to a grand jury and tries the indictment in Norfolk Superior Court. The office accepted the suicide ruling and brought no case.

The United States Attorney’s Office charged Mr. Farwell instead, under a federal statute that makes it a crime to kill a person in order to stop that person from reporting a federal crime. Massachusetts has its own witness intimidation statute, G.L. c. 268, § 13B, and its own strangulation statute, G.L. c. 265, § 15D. The Commonwealth has used neither.

Count One charges Mr. Farwell under 18 U.S.C. § 1512(a)(1)(C) with killing a witness or victim. The jury must find beyond a reasonable doubt that he killed Ms. Birchmore with malice aforethought, which is the state of mind required for murder, and with the intent to prevent her, or anyone else, from telling a law enforcement officer about the commission or possible commission of a federal offense.

The indictment names three federal offenses that it alleges he wanted to hide. The first is deprivation of rights under color of law, 18 U.S.C. § 242, which punishes a police officer who uses his official position to violate a person’s constitutional rights. The second is coercion and enticement, 18 U.S.C. § 2422(b), which punishes an adult who uses a phone or the internet to persuade a child under 18 to engage in sexual activity that is a crime. The third is wire fraud, 18 U.S.C. § 1343, based on the allegation that he collected his police pay for hours he spent with her and concealed that from the department.

The statute requires the government to prove a federal connection. The Supreme Court held in Fowler v. United States, 563 U.S. 668 (2011), that where a defendant kills to prevent communication with law enforcement generally, the government must show a reasonable likelihood that at least one relevant communication would have been made to a federal officer. Before trial, Judge Casper denied Mr. Farwell’s motion to dismiss the indictment, including his argument that the indictment failed to allege a federal connection.

Count Two, added by a superseding indictment on October 28, 2025, charges Mr. Farwell under the Unborn Victims of Violence Act, 18 U.S.C. § 1841, with causing the death of the child in utero during the killing. The statute does not require the government to prove that he knew she was pregnant.

If the jury convicts Mr. Farwell on either count, the judge must sentence him to life in prison. On January 20, 2026, the Department of Justice notified the court that it would not seek the death penalty. Mr. Farwell has been held without bail since his arrest, at a detention facility in Rhode Island. On October 1, 2026, Judge Casper denied his motion to move the trial to Rhode Island.

What the Jury Must Decide

The central dispute at trial is how Sandra Birchmore died. The government says Mr. Farwell strangled her. The defense says she hanged herself. Judge Casper ruled in September 2026 that the government’s medical experts may testify that she was strangled, that the defense may present evidence of her mental health history, and that her journals, text messages and social media posts are admissible.

Assistant United States Attorney Torey Cummings told the jury that Mr. Farwell first had sex with Ms. Birchmore when she was 15 and he was 27, that he used her admiration for police officers to control her for the rest of her life, and that he killed her after her friend’s call to the police department, because he feared that she would expose him.

She said that Ms. Birchmore held information that could end his career and his freedom, and that he ended her life first. She told the jury that the government’s medical witnesses will testify that Ms. Birchmore’s injuries are far more consistent with homicide than with suicide, and that Mr. Farwell counted on everyone who saw a vulnerable young woman tied to a door handle to assume that she had killed herself.

Defense attorney Kimberly Stevens told the jury that Mr. Farwell had an affair with Ms. Birchmore and made regrettable mistakes, but did not kill her. She said that he went to the apartment that night to end the relationship and told her the baby was not his, and that Ms. Birchmore, alone, with a few dollars in her bank account, and abandoned by the man she loved, took her own life.

She told the jury that no forensic evidence of Mr. Farwell was found under Ms. Birchmore’s fingernails, that FBI meeting notes recorded that federal examiners at first saw no evidence contradicting the suicide finding, and that Ms. Birchmore had attempted suicide once as a young teenager.

The jury will decide one question, whether the government has proved beyond a reasonable doubt that Mr. Farwell killed Ms. Birchmore to silence her. The question of what the adults around her owed her is different, and the answer is already in the public record.

The Stoughton Police Department’s own investigation found that a 27-year-old officer who was her instructor began a sexual relationship with her when she was 15, and that two more officers of the same department had sexual relationships with her when she was an adult.

A friend reported the relationship to the police. Someone at the department then told the officer. Police found Ms. Birchmore dead three days after that officer visited her apartment. The state investigators accepted that she had killed herself, and the Commonwealth closed the case.

Those facts are established whatever the jury decides about the night of February 1, 2021. No Massachusetts prosecutor has charged anyone for any of them.

The Trial Schedule and What Comes Next

Jury selection began on October 6, 2026, from a pool of more than 400 prospective jurors who completed questionnaires. The lawyers delivered their opening statements on October 9. Testimony began on October 13 and is expected to continue into November. Federal courts do not allow cameras, so there is no video of the trial.

The witness lists include William Farwell. Later posts will cover the medical testimony on how Ms. Birchmore died, the cross-examination of the investigators who ruled her death a suicide, and the verdict.

Key Takeaways

• Sandra Birchmore was 23 years old and eight to ten weeks pregnant when she died in Canton on February 1, 2021. State investigators and the medical examiner ruled her death a suicide. In April 2026 the medical examiner changed the manner of death to undetermined.
• The Stoughton Police Department’s internal investigation found in 2022 that three of its officers had sexual relationships with Ms. Birchmore, whom they met through the department’s Explorers program when she was 12, and that Matthew Farwell’s relationship with her began when she was 15 and he was 27. All three resigned. No Massachusetts prosecutor has charged any of them.
• Twelve days before she died, a friend reported the relationship to the Stoughton police. The indictment alleges that a department employee told Mr. Farwell about the call.
• A federal grand jury charged Matthew Farwell with killing Ms. Birchmore to prevent her from reporting federal crimes, 18 U.S.C. § 1512(a)(1)(C), and with causing the death of her unborn child, 18 U.S.C. § 1841. If the jury convicts him on either count, the judge must sentence him to life in prison. The government is not seeking the death penalty.
• The trial before Chief Judge Denise J. Casper began with opening statements on October 9, 2026, and is expected to last about five weeks. The central dispute is whether Ms. Birchmore was strangled or died by suicide.
• Mr. Farwell has pleaded not guilty. His lawyer concedes the affair and denies the killing.

Related Serpa Law Office resources

• How the Men of Cornell University Failed Jane Doe: The Cornell Fraternity Rape Case Under New York and Massachusetts Law
• Sexual Assault and Rape Defense in Massachusetts
• Consent in Massachusetts Rape and Sexual Assault Cases
• Intimidation of a Witness (G.L. c. 268, § 13B)
• Strangulation or Suffocation in Massachusetts (G.L. c. 265, § 15D)
• Massachusetts Grand Jury Indictments: How Superior Court Cases Begin
• Opening Statements and Closing Arguments in Massachusetts Criminal Trials
• Cross-Examination in Massachusetts Criminal Trials
• Massachusetts Text Message and Phone Evidence FAQs