Farwell, who had pleaded not guilty, was found guilty on both counts after the second full day of deliberations in Boston's federal court. The trial, which began last month, featured testimony from Farwell's twin brother, William, who admitted to having extramarital sex with Birchmore when she was an adult and acknowledged receiving immunity in exchange for his testimony. Farwell declined to take the stand in his own defense.

Birchmore, 23, was found dead in her Canton apartment on Feb. 1, 2021. She was pregnant at the time. Her death was initially ruled a suicide, but the case drew new scrutiny in 2022 when Stoughton's police chief held a news conference revealing that three former officers had inappropriate sexual relationships with Birchmore, one when she was a girl. The officers, including the Farwell brothers, resigned during the investigation.

Federal prosecutors alleged that Farwell killed Birchmore to prevent her from revealing their relationship and the alleged crimes connected to it. At the time of his indictment in 2024, then-acting U.S. Attorney for Massachusetts Joshua Leavy said, "Sandra Birchmore survived years of grooming, statutory rape and then sexual violence, all at the hands of Matthew Farwell, who was employed throughout the relationship as an officer and then detective for the Stoughton Police Department."

Stoughton police have said the relationship began when Birchmore was 15 and enrolled in the department's police explorer program.

Farwell was not charged with murder in the federal case because murder is generally prosecuted by the state. He has not been charged in state court; the Norfolk District Attorney's Office has called the case "an ongoing and pending criminal matter."

The case has continued to reverberate in Stoughton. The town's police chief, Donna McNamara, and Town Manager Thomas Calter are both on leave amid an outside investigation into McNamara's claim that Calter tried to force her out of her job. Her lawsuit alleges that Calter told her to destroy a second internal investigation about the case, which she has denied doing.

Birchmore's estate has filed a civil lawsuit against the Town of Stoughton, Farwell and others. A hearing in that case is scheduled after the federal trial concludes.

The verdict brings a measure of accountability, but questions remain about how a police department allowed a culture in which an officer could prey on a teenager for years. For Birchmore's family and supporters, the conviction is a long-sought acknowledgment of what they say was a grave injustice.

If you or someone you know is experiencing domestic violence, contact the National Domestic Violence Hotline at 1-800-799-SAFE (7233) or visit www.thehotline.org.