BOSTON, MA — What began as a police conclusion that Sandra Birchmore died by suicide has turned into a federal murder trial centered on a Massachusetts detective and a deeply disputed investigation. Federal prosecutors say Matthew Farwell killed Birchmore, then tried to make her death appear self-inflicted after years of sexual abuse that began when she was a teenager.
Farwell, 40, is being tried in federal court in Boston. Birchmore was 23 when she was found dead in her Massachusetts home, and her friends immediately questioned the suicide finding. They told investigators she had recently learned she was pregnant and was excited about the pregnancy, while Farwell was the person most threatened by it.
Prosecutors say the first investigation missed key warning signs
Assistant U.S. Attorney Torey Cummings told jurors that state police troopers working in the Norfolk County district attorney’s office moved too quickly to label the death a suicide and never seriously tested that conclusion. He said Farwell was interviewed for only 15 minutes in a parking lot, with no notes taken, no visible injuries documented and no DNA sample collected.
Investigators did review Farwell’s phone, but only after he had already deleted his text messages with Birchmore. Cummings said police also told the medical examiner there was no foul play, reinforcing a suicide determination that federal prosecutors now say was wrong from the beginning. The original response, he argued, helped shield Farwell while evidence was still fresh.
A friendship built through a police mentoring program became a sexual relationship
Birchmore first met Farwell when she was 12 through a Stoughton police mentoring program for children interested in law enforcement. Farwell was 24 at the time and later friended her on Facebook. Over the years, the two exchanged roughly 40,000 text messages, many of which were read to jurors during the trial.
Prosecutors say those messages show the relationship became sexual when Birchmore was 15 and Farwell was 27. In one 2020 message, Birchmore wrote that she would never forget the day they first had sex, identifying April 10, 2013. Farwell replied, “Me too,” after she called it the “best day of my life.”
Jurors also heard messages prosecutors say reveal violent sexual fantasies, including one in which Farwell wrote, “I’ll grab your throat and say you won’t say a word to anyone or you will be sorry.”
Pregnancy intensified the conflict between Birchmore and Farwell
According to prosecutors, the relationship became more volatile in 2020 after Birchmore pressed Farwell to get her pregnant and threatened to tell his wife if he refused. When she later became pregnant, she sent him a text image that read, “Congrats, we are going to be parents.” Farwell responded that he had “nothing to say.”
When Birchmore suggested he should be present when the baby was born, he answered, “You are truly the worst person on the face of the earth.” A friend, Leslie Davis, testified that Birchmore described fights with Farwell, including one in which she said he pushed her to the ground after she wanted him to acknowledge paternity on a birth certificate.
Prosecutors say Birchmore was about eight weeks pregnant when she died. They argue the pregnancy gave Farwell a powerful motive to silence her before the relationship and the abuse became public.
Federal investigators say the death scene fit strangulation, not suicide
The FBI reopened the case in 2023 after concerns were raised by former Stoughton Deputy Chief Brian Holmes, who had conducted an internal affairs investigation. Holmes left before his findings were released, but prosecutors say that inquiry concluded Farwell had a sexual relationship with Birchmore.
An expert called by federal authorities, Dr. William Smock, testified that Birchmore was strangled with a duffel bag strap and struggled before she died. Prosecutors say that version of events fits the timeline from security footage and digital records better than the original suicide ruling.
Video showed Farwell entering Birchmore’s apartment building at 9:14 p.m. on Feb. 1, 2021. A digital forensics expert testified that Birchmore’s phone stopped moving at 9:40 p.m., three minutes before lobby video showed Farwell leaving.
Defense argues Birchmore was struggling and Farwell did not kill her
Farwell’s lawyer, Kimberly Stevens, acknowledged to jurors that he “had an affair” but said he did not kill Birchmore. She described Birchmore as emotionally troubled, noting that she began psychiatric medication at age 6, attempted suicide as a teenager and was under heavy stress after becoming pregnant.
Stevens said Birchmore was alone for the holidays and had less than $3 in the bank. She told jurors that Farwell went to her apartment to end the relationship, not to commit murder. Her argument is that Birchmore was suicidal and that the circumstances of her death were misunderstood from the start.
The state medical examiner initially ruled Birchmore’s death a suicide, relying in part on information from police. That office later changed the official cause of death to “undetermined,” leaving the criminal case to turn on competing interpretations of the evidence now before the jury.
Paternity evidence and the case timeline are now before the jury
Prosecutors also presented paternity evidence showing Farwell was not the father of Birchmore’s baby. They said the biological father was Army recruiter Jason Pickard, who testified that he met Birchmore in 2019 while she was considering enlisting and soon began a sexual relationship with her.
Pickard testified that Birchmore told him Farwell was the father and that their relationship with Farwell had started when she was underage. Prosecutors finished presenting their case on Wednesday, and the defense was expected to call witnesses for a third day on Friday before the matter goes to the jury as early as next week.
The trial has put the first police response under the same scrutiny as Farwell’s conduct. Jurors must now decide whether Birchmore died by suicide, as police first concluded, or whether prosecutors have proved that Farwell killed her to keep the relationship hidden.
