Detectives from the Stoughton Police Department testified Wednesday in the trial of Matthew Farwell, providing insight into his behavior in the months leading up to the death of Sandra Birchmore, a pregnant 23-year-old woman. Farwell is charged federally with killing Birchmore and causing the death of her unborn child.

According to testimony, Farwell’s demeanor noticeably shifted toward the end of 2020 and early 2021. Detective Sandra Barrett described Farwell as increasingly agitated during that period. Barrett recounted an incident in late January 2021 when she encountered Farwell at a local bar and asked if everything was all right. Farwell acknowledged having personal issues involving a woman who was not his wife, who was threatening to reveal an affair. Despite this, Farwell reportedly assured Barrett that the matter would resolve itself.

Another Stoughton detective, Daniel Barber, also observed a change in Farwell’s behavior. Barber, who serves as president of the patrol officers union and has a long-standing friendship with Farwell, testified that Farwell had previously been known for remaining calm under pressure. However, during the transition from 2020 into 2021, Farwell grew increasingly stressed, frequently sending text messages and taking calls, including during times when the two officers were alone on duty. Barber recounted a car ride to Taunton for work when he confronted Farwell about the situation. Farwell responded, “I gotta put crazy back in the bag,” and told him “everything will be all right.”

Prosecutors allege that Farwell killed Birchmore by strangling her and staged the scene to resemble a suicide in order to conceal previous misconduct, including allegations that he groomed and sexually exploited Birchmore from a young age. Farwell has pleaded not guilty, and his defense counters that Birchmore, who suffered from mental health issues, took her own life by hanging after he ended their relationship. They argue she feared for the health of the baby, whom she believed was fathered by Farwell. Forensic evidence has since excluded Farwell as the father.

The Stoughton officers were among several witnesses who testified Wednesday regarding Birchmore’s pregnancy and Farwell’s involvement in the case. The trial continues as the court examines conflicting accounts of the circumstances surrounding Birchmore’s death.