The federal murder case over Sandra Birchmore's 2021 death in her Canton apartment has taken a new turn. Defense attorneys for former Stoughton officer Matthew Farwell allege prosecutors pressured a medical examiner to alter her ruling in the case, a claim raised in a federal court filing that marks the latest development in a case that has drawn scrutiny of law enforcement across Norfolk County.

Farwell, who has pleaded not guilty, faces federal murder charges filed in August 2024. Prosecutors allege he strangled Birchmore, 23, and staged the scene to look like a suicide after she told him she was pregnant with his baby, according to CBS Boston.

The defense has said DNA tests showed Farwell was not the father.

The defense allegation, first reported by LAmag's Michele McPhee on Aug. 28, targets the process behind a key change in the case record. The Massachusetts Office of the Chief Medical Examiner (OCME) amended Birchmore's death certificate, changing the cause of death from "asphyxia by hanging" to "asphyxia" and the manner of death from "suicide" to "undetermined," CBS Boston reported on May 1.

That change is central to both sides' strategies. The defense had pointed to the original suicide ruling as evidence Farwell did not kill Birchmore. Defense attorneys also noted that prosecutors obtained a second opinion from a forensic pathologist who agreed with the ME's initial finding of suicide.

In a March 26 court filing, Farwell's defense attorneys argued that whether Birchmore's death was a suicide or a homicide is the central question in the case, and that the government bears the burden of proving it beyond a reasonable doubt.

Birchmore's cousin Barbara Wright told CBS Boston in May that the amended ruling was "a huge step towards getting justice for Sandra and her baby, her unborn son."

The OCME said in a statement that its findings reflect the information available at the time and may be updated as new information emerges.

Federal prosecutors say the medical examiner is expected to testify at trial to explain why the ruling changed, according to an NBC Boston report on the government's trial brief. The prosecution is being led by U.S. Attorney Leah B. Foley for the District of Massachusetts.

The case has also drawn scrutiny of the Norfolk County District Attorney's office. Longtime DA Michael Morrissey announced in January he would not seek reelection after 16 years. His office's handling of the Birchmore case, which was initially ruled a suicide without criminal charges, has been cited as a factor in the contested race to replace him.

An internal Stoughton police investigation found that Farwell's twin brother, former officer William Farwell, and ex-deputy chief Robert Devine also had inappropriate relationships with Birchmore, according to CBS Boston. Both have been decertified as police officers in Massachusetts.

Farwell is being held without bail. His trial is scheduled for October 2026. Anyone with information related to the case can contact the FBI's Boston field office at 857-386-2000.