Sandra Birchmore’s longtime therapist is expected to return to the witness stand Monday before Matthew Farwell’s trial shifts to medical testimony about Birchmore’s cause and manner of death.
Diala Alkhalil, a licensed mental health counselor, began testifying on Friday, telling the jury that Birchmore was a resilient “fighter” who struggled with anxiety and grief before her death but was not suicidal.
Alkhalil’s account of Birchmore’s state of mind is a prelude to testimony about the key question in the case against Farwell, a former Stoughton police detective: Was Birchmore strangled, as the prosecution alleges? Or did she kill herself, as the defense insists?
Dr. María Del Mar Capó-Martínez, a forensic pathologist at the state Office of the Chief Medical Examiner, is expected to delve into evidence from Birchmore’s autopsy once Alkhalil’s testimony concludes. Her testimony will mark the first time she’s commented publicly on the case in any detail.
Capó-Martínez autopsied Birchmore’s body on Feb. 5, 2021, a day after police found her dead at her Canton apartment.
In May 2021, she ruled the 23-year-old Birchmore, who was pregnant, died by hanging herself. DNA testing revealed Farwell did not impregnate Birchmore, though prosecutors said they were trying to conceive and believed they had done so.
Federal prosecutors assert Capó-Martínez’s suicide determination was a “premature” finding based on incomplete evidence and a “significant amount of misinformation.”
When she reached her conclusion, prosecutors said, Capó-Martínez did not know about text messages exchanged by Birchmore and Farwell in which they discussed the beginning of their sexual contact: an alleged act of aggravated statutory rape when Birchmore was a 15-year-old Stoughton police Explorer and Farwell was a 27-year-old police officer who taught in the program.
Prosecutors said Capó-Martínez also did not know that Farwell and Birchmore engaged in choking during sex or see surveillance video showing Farwell entering and exiting Birchmore’s apartment building on Feb. 1, 2021, the last time anyone heard from her.
In April, Capó-Martínez withdrew the suicide opinion and ruled Birchmore’s manner of death was undetermined.
Prosecutors allege Farwell killed Birchmore to keep her from revealing his alleged federal crimes. The accusations are coercion and enticement, which involves sexual abuse; deprivation of rights under color of law, an allegation that Farwell abused his police authority to exploit Birchmore; and wire fraud, claims that he stole from the town of Stoughton by meeting Birchmore for sex while was on duty.
Farwell, 40, has pleaded not guilty.
Farwell’s defense has suggested that federal prosecutors pressured Capó-Martínez to revise her determination in Birchmore’s case.
His lawyers assert Birchmore hung herself after Farwell ended their relationship and denied impregnating her.
The defense further said Birchmore had a long history of mental illness and previously tried to kill herself. Her final days were marked by financial trouble and worries about the viability of her pregnancy, Farwell’s attorneys told the jury.
Capó-Martínez’s suicide determination factored into the decision by Norfolk District Michael W. Morrissey to not bring criminal charges in Birchmore’s death.
In 2023, the FBI opened its own investigation based on referrals from a civilian and two police officers, according to trial testimony.
As part of the probe, the FBI consulted with Dr. William Smock, who reviewed Birchmore’s autopsy and determined she was strangled. Prosecutors plan to call Smock later this week.
Smock is known for testifying in the 2021 trial of Derek Chauvin, the former Minneapolis police officer convicted of killing George Floyd by pressing a knee on his neck for nine and a half minutes.
The defense plans to offer testimony from Dr. Thomas Andrew, a board-certified forensic pathologist and former chief medical examiner in New Hampshire.
Andrew could not determine Birchmore’s manner of death but said he could not rule out the possibility she hanged herself, court papers show.
Laura Crimaldi can be reached at laura.crimaldi@globe.com. Follow her @lauracrimaldi. Sean Cotter can be reached at sean.cotter@globe.com. Follow him @cotterreporter.