By Basant El-Faramawy
Closing arguments are expected Friday in the federal trial of former Massachusetts police officer Matthew Farwell, who is accused of killing 23-year-old Sandra Birchmore in 2021 to conceal a sexual relationship that began when she was 15.
Prosecution alleges staged suicide
Federal prosecutors say Farwell, then a married detective with the Stoughton Police Department, killed Birchmore and attempted to stage her death as a suicide after learning she was pregnant with what he believed was his child. Birchmore had participated in a youth program run by the department as a child.
Defense denies murder, disputes timeline
Farwell’s lawyers acknowledge an extramarital relationship but argue he did not kill Birchmore and that the sexual relationship began only after she became an adult. They contend Birchmore, who was facing financial and personal struggles, took her own life.
Initial investigation ruled suicide
Local police and Massachusetts State Police investigators, some with personal ties to Farwell, quickly concluded Birchmore’s death was a suicide. The state medical examiner initially ruled the same, but later changed the cause of death to “undetermined.” Birchmore’s friends and family never accepted the suicide finding, noting she had been excited about her pregnancy and had prepared for the baby’s arrival.
FBI uncovers extensive text messages
The FBI opened an investigation in 2023 after a former Stoughton deputy chief raised concerns. Investigators found about 40,000 text messages between Farwell and Birchmore, including exchanges referencing sex when she was 15 — below the age of consent in Massachusetts. Texts also showed growing tension as Birchmore pressed Farwell to father a child and threatened to reveal their relationship to his wife.
Forensic evidence and expert testimony
A digital forensics expert testified that Birchmore’s phone stopped moving at 9:40 p.m. on Feb. 1, 2021, three minutes before a lobby camera recorded Farwell leaving her building. Prosecution expert Dr. William Smock said injuries indicated strangulation with a duffel bag strap and a struggle. Defense expert Dr. Thomas Andrew, former chief medical examiner of New Hampshire, concluded the evidence pointed to hanging.
Paternity test and mental health history
A paternity test later revealed a different man was the father of Birchmore’s unborn child. The defense highlighted Birchmore’s long-standing mental health challenges, including psychiatric medication from age 6, a teenage suicide attempt, and journal entries about suicide.
