A former Stoughton police detective is facing a federal trial on charges that he killed a woman and staged her death as a suicide. Matthew Farwell, 40, is accused of strangling 21-year-old Sandra Birchmore at her Canton apartment in February 2021. Prosecutors allege Farwell killed Birchmore after she told him she was pregnant and identified him as the father. DNA evidence later showed he was not the father of the unborn child.
The case follows an initial investigation by the Massachusetts State Police, which concluded that Birchmore had died by suicide. Federal authorities later opened their own investigation, leading to an August 2024 indictment. The trial involves conflicting findings between state and federal investigators, with the state medical examiner currently listing the manner of Birchmore’s death as undetermined.
During testimony on Oct. 22, 2026, Jason Pickard, an Army recruiter, identified himself as the father of Birchmore’s unborn child. Pickard, who was granted immunity, testified that he had a 14-month sexual relationship with Birchmore but said she had insisted Farwell was the father. Forensic scientist Betsey Duval testified that DNA found on the ligature around Birchmore's neck was inclusive of Farwell's profile, though defense attorneys noted Duval had interpreted the results rather than conducting the laboratory tests herself.
Additional testimony came from women who reported having sexual affairs with Farwell while he was married. Prosecution witnesses also highlighted gaps in the initial state investigation, noting that State Police investigators did not attend Birchmore's autopsy, failed to seek search warrants for Farwell's home or vehicle, and conducted informal interviews in parking lots without recording them. FBI Special Agent Heidi Kelsch testified that federal investigators reviewed approximately 40,000 messages between Farwell and Birchmore, many of which had not been examined by state authorities.
The trial examines the conduct of local law enforcement and the integrity of state death investigations. Federal investigators allege Farwell's sexual contact with Birchmore began when she was a 15-year-old in the Stoughton Police Explorers program. The outcome will determine whether Farwell faces life in prison or acquittal for the 2021 death.
The proceedings involve at least 130 witnesses and hundreds of thousands of digital messages. For the public, the trial provides a look at how different agencies can reach opposite conclusions regarding a death: one labeling it a suicide and the other a homicide. Federal prosecutors are presenting criminal charges against Farwell while critiquing the initial handling of the scene.
The trial also involves federal intervention in a local death investigation where a police officer is a suspect. The scale of the investigation involves the review of years of medical records, school documents, and GPS data across multiple digital platforms. If convicted, Farwell faces federal sentencing guidelines for a capital crime. The trial resumed following a recess on Oct. 22, 2026, with further testimony expected to address DNA evidence and the timeline of events leading to the discovery of Birchmore's body on Feb. 4, 2021.