A State Police investigator testified Wednesday that state detectives failed to collect a broken necklace found on Sandra Birchmore's body and did not seize a duffel bag believed connected to the strap she was found hanging from, according to The Boston Globe. The omissions are central to prosecutors' case against Matthew Farwell, the former Stoughton police detective accused of strangling the 23-year-old woman at her Canton apartment in February 2021.
State Trooper Matthew Dunne also testified that investigators did not immediately seek to interview Farwell even after learning from Birchmore's colleagues that she was pregnant, believed Farwell was the father, and that he was a married police detective with children. The testimony illustrates how state authorities missed or failed to pursue leads that might have changed the course of the investigation.
How a suicide ruling became a murder investigation
Birchmore was 8 to 10 weeks pregnant when she died and had told Farwell that he was the father. The state medical examiner originally ruled her death a suicide, and the Norfolk district attorney declined to bring charges based on that determination, according to The Boston Globe. The state medical examiner has since changed the manner of death to undetermined.
For years, the case stalled. Federal authorities became involved after an independent medical examiner working with them concluded Birchmore's injuries were consistent with strangulation, not suicide. A federal grand jury indicted Farwell in 2024, and the FBI arrested him in August 2024. He has been held without bail at a Rhode Island detention facility since his arrest.
Key evidence collected after initial investigation
Dunne testified that he interviewed Farwell in an elementary school parking lot days after Birchmore's death. The conversation was not recorded and he did not take notes. "We wanted to make sure we got a statement out of him, whether truthful or otherwise," Dunne said, according to The Boston Globe.
Farwell admitted he visited Birchmore's apartment on the night she died, but told investigators he went there to end the relationship and to tell Birchmore the child was not his, Dunne testified under cross-examination.
The allegations against Farwell
Farwell, 40, is charged with killing Birchmore and causing the death of her fetus. Prosecutors allege he groomed Birchmore for child sexual abuse, initiated an illegal sexual relationship with her when he was 27 and she was 15, and met her for sex while on duty, according to The Boston Globe. Farwell and Birchmore met after she enrolled in the Stoughton Police Department Explorers Program in 2010, the year she turned 13. Farwell participated in the program as a youth and stayed involved as a volunteer instructor.
To secure a conviction in Birchmore's death, prosecutors must prove that Farwell killed her to stop her from reporting that he committed a crime. Farwell would face life in prison if convicted.
Defense strategy focuses on mental health history
Defense attorneys sought to emphasize Birchmore's mental health during cross-examination. Dunne testified that Birchmore's coworkers told investigators she had discussed anxiety and possible depression, and a relative reported that she had been diagnosed with bipolar disorder and experienced mental health crises involving suicidal statements and hospitalization, according to The Boston Globe.
The trial centers on a fundamental dispute: whether Birchmore was strangled or died by suicide. Farwell's defense attorneys argue that she was upset because he was ending their relationship.