A federal jury in Boston on Tuesday, Nov. 10, convicted former Stoughton, Massachusetts, police officer Matthew Farwell of killing Sandra Birchmore and causing the death of her unborn child. The U.S. Attorney's Office for Massachusetts announced the verdict as "guilty on both counts."
The jury had told U.S. District Judge Denise J. Casper on Monday that it was deadlocked. Deliberations resumed Tuesday morning, and the verdict came that afternoon.
Farwell was convicted of killing a witness or victim under 18 U.S.C. § 1512, and of a second count under the federal law that protects unborn children. The Justice Department did not seek the death penalty. The witness-killing law takes its penalties from the federal murder statute, which sets death or life in prison for first-degree murder. Judge Casper will set the sentencing date.
What prosecutors charged
The superseding indictment, returned Oct. 28, 2025, sets out what prosecutors had to prove.
Birchmore was born in May 1997. She applied to the Stoughton Police Explorers, a program that teaches local young people about police work, in March 2010, when she was 12. Farwell, a volunteer with the program, became an instructor when he joined the Stoughton police in 2012, and he stayed on the force until about April 2022.
The indictment says Farwell had sex with Birchmore before she turned 16 and kept up sexual contact with her until early 2021, sometimes during shifts when he was supposed to be on duty. In December 2020 she learned she was pregnant and told him he was the father.
On Jan. 20, 2021, a friend of Birchmore's called the Stoughton Police Department to report that Farwell was having sex with her. Soon after, someone at the department told Farwell about the call.
On or about Feb. 1, 2021, prosecutors charged, Farwell strangled Birchmore in her apartment in Canton and staged the scene to look like a suicide. Birchmore was 23 and was carrying a boy at 8 to 10 weeks of gestation.
Why it was a federal case
The witness-killing count required prosecutors to show that Farwell killed Birchmore to keep her from telling law enforcement about federal crimes. The indictment named three: deprivation of rights under color of law, coercion and enticement of a minor, and wire fraud. The unborn-child count rests on that same conduct. The indictment also says he hid the time he spent with Birchmore while on duty from the department, which required officers to report their hours accurately to be paid.
Prosecutors first announced Farwell's arrest on Aug. 28, 2024, more than three years after Birchmore's death, and added the unborn-child charge in the superseding indictment 14 months later. The U.S. Attorney's Office keeps the charging documents and its announcements on its case page.
