Matthew Farwell trial: Farwell’s twin brother back on the stand

BOSTON — The twin brother of Matthew Farwell will be back on the stand Tuesday when court gets underway.

Farwell is accused of killing Sandra Birchmore and her unborn baby.

Farwell’s twin brother William, who allegedly also had a sexual relationship with her, is now on the stand.

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What happened on Monday?

William Farwell revealed Monday that he agreed to testify under a grant of immunity, meaning his statements cannot be used against him.

Farwell took the stand for just under 20 minutes.

He admitted to having a sexual relationship with Sandra Birchmore when she was of legal age while he was working on duty as a Stoughton police officer.

Farwell testified that he met Birchmore when she was 20 or 21 in the summer of 2018 and that their consensual relationship began at that time.

He also said that at the time, he did not know anything about his brother, Matthew Farwell, having sex with Birchmore.

Jurors did not hear much more from William Farwell before court wrapped for the day.

Most of Monday’s testimony came from Dr. Maria Del Mar Capo Martinez, the medical examiner in the case.

Capo Martinez originally determined Birchmore’s cause of death to be asphyxia by hanging and the manner of death to be suicide.

More than five years later, she changed the death certificate after new information came to light. Birchmore’s cause of death is now listed as asphyxia, with the manner of death listed as undetermined.

Capo Martinez was adamant that she was not pressured to change the death certificate.

The defense brought up that Capo Martinez met with the FBI and U.S. Attorney’s Office in 2024, when a forensic expert shared a different opinion about what happened to Birchmore.

This is a developing story. Check back for updates as more information becomes available.

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