A former Stoughton, Massachusetts police detective is on trial in federal court, charged with killing Sandra Birchmore, 23, and her unborn son in Canton in February 2021, a death first ruled a suicide. He has pleaded not guilty; his lawyers say she took her own life.
Farwell's trial opened in federal court in Boston with jury selection on Oct. 6, 2026, and opening statements on Oct. 9.306 Testimony began Oct. 13. In the first week of testimony the jury heard from Stoughton police officers, the State Police trooper who worked the original death investigation, a state toxicologist, a friend of Birchmore's, and FBI witnesses who read aloud text messages between the two.781012 In the second week, the jury heard from Birchmore's obstetrician, a Stoughton police dispatcher, friends and police colleagues, the man DNA testing identified as the father of her unborn child, and a State Police DNA analyst who testified that DNA on the ligature included Farwell's.15161718 In the third week, the state pathologist who performed the autopsy testified that she changed the manner of death to undetermined after learning more about the case, Farwell's twin brother testified under a grant of immunity, and the government's forensic expert testified that Birchmore was strangled.2322 The prosecution rested on Oct. 28, and the defense began calling witnesses, including the state's chief medical examiner and a psychiatrist who testified about suicide risk factors.242628
Farwell has not been convicted. What follows is what the indictment and prosecutors allege, what the defense argues, and what witnesses have said in testimony so far. Testimony is evidence for the jury to weigh, not a finding.75
A federal grand jury in Boston indicted Farwell in August 2024 on one count of killing a witness or victim, under 18 U.S.C. § 1512(a)(1)(C).1 The count alleges that he killed Sandra Birchmore on or about Feb. 1, 2021, in Canton, to prevent her from telling law enforcement about possible federal crimes: deprivation of rights under color of law (18 U.S.C. § 242), coercion and enticement of a minor (18 U.S.C. § 2422(b)) and wire fraud (18 U.S.C. § 1343).14 Prosecutors say the wire-fraud theory rests on alleged time theft from the town: shifts on which, they allege, he was with Birchmore while recorded as working.113 A superseding indictment returned Oct. 28, 2025, added a second count under 18 U.S.C. § 1841, alleging that the killing caused the death of her unborn child.45
He was arrested on Aug. 28, 2024.3 He pleaded not guilty, and a magistrate judge ordered him held pending trial after his lawyers waived a detention hearing.37 He has pleaded not guilty to both counts.7 When the first indictment was announced, the charge carried a mandatory sentence of death or life in prison.3 In December 2025, prosecutors filed a notice that they would not seek the death penalty, on the instruction of the U.S. attorney general, according to court records; the notice gave no reasons.35
According to the indictment, Farwell was a Stoughton police officer from 2012 until April 1, 2022, and an instructor in the department’s Police Explorers program, a vocational program for local young people interested in law enforcement careers.4 Birchmore, born in May 1997, applied to the program at 12, in about March 2010, and took part until about 2016.4 The indictment alleges that Farwell engaged in sexual intercourse and other sex acts with her before she turned 16, that the sexual contact continued until about early 2021, and that some of it took place during on-duty shifts he did not report to the department.4 An FBI affidavit alleges the abuse began no later than April 2013, when she was 15 and he was 27.2
The indictment alleges that in about December 2020 Birchmore learned she was pregnant and told Farwell he was the father.4 On about Jan. 20, 2021, according to the indictment, a friend of hers called the Stoughton Police Department about the relationship, and a department employee told Farwell about the call.4 It alleges that on about Feb. 1, 2021, he killed her by strangulation and staged her apartment to look like a suicide.4 At her death she was pregnant with a male child estimated at 8 to 10 weeks’ gestation, the indictment says.4
Prosecutors say in court documents that in fall 2020 Farwell agreed to try to get Birchmore pregnant to keep her from disclosing their relationship, and that when she told him she was “keeping it,” he called her the “worst person on the face of the earth.”5
An FBI affidavit filed in support of detention says Birchmore told Farwell on Dec. 28, 2020, that she was pregnant, and that she wanted him involved and asked about the birth certificate and the child’s last name.2 It says witnesses reported that Birchmore told them Farwell had been physically aggressive toward her in the weeks before her death.2 According to the affidavit, Farwell asked her for a key to her apartment around Jan. 24, 2021; she had a copy made that day, and texts indicate he looked through her closet and bathroom, which the agent describes as planning.2
The affidavit says building video, corrected for a clock about 13 minutes off, shows Farwell entering at 9:14 p.m. on Feb. 1, 2021, and leaving at 9:43 p.m.; her phone’s last recorded movement was at 9:40 p.m., and it recorded none after that before police recovered it on Feb. 4.2 In a Feb. 6, 2021 interview with State Police, according to the affidavit, Farwell denied any involvement in her death and made statements the government says were false, including that the relationship began in 2020 and that he left around 9:30 p.m.2
In early May 2021, a pathologist with the state Office of the Chief Medical Examiner ruled the cause of death asphyxia by hanging and the manner suicide.2 The pathologist who performed the autopsy has not spoken publicly; her office said the conclusion was “based on the evidence available at the time of determination.”36
The government retained Dr. William Smock, an emergency and forensic physician, who concluded the death was a homicide, according to the FBI affidavit.2 He cited a fracture of the right hyoid bone in the neck that he says is inconsistent with a seated hanging, a buckle imprint on the upper chest, abrasions to the nose and a broken necklace.2 A forensic pathologist who reviewed the autopsy for Birchmore’s estate also concluded she was strangled.36 Only the state pathologist examined the body; the others reviewed records.36
In 2026, the medical examiner’s office amended the death certificate, changing the cause to “asphyxia” and the manner from suicide to undetermined; a spokesperson confirmed the change but did not explain it.33
Farwell’s lawyers asked to move the trial to Rhode Island, arguing that “voluminous pretrial publicity” could taint the jury pool; prosecutors opposed the request.34 On Oct. 1, 2026, Judge Denise J. Casper denied the defense’s request to move the trial, finding it had “not met the high burden of demonstrating that pretrial publicity” would prevent a fair trial in the district.32
The trial opened with jury selection on Oct. 6, 2026, and a jury of 16, including alternates, was seated.307 In her opening on Oct. 9, prosecutor Torey Cummings told the jury Farwell “strangled Sandra to death” and staged a suicide, and argued that the medical examiner ruled without knowing of what the government alleges was his past strangling of Birchmore.6 “She could end his life with the information she had, so he was going to end hers first,” Cummings said, according to CBS Boston.7
Defense attorney Kimberly Stevens told the jury Farwell had an affair and made mistakes but did not kill her.6 She pointed to the medical examiner’s suicide ruling, to the three and a half years before federal authorities took up the case, and to a scene she said showed no signs of a struggle, with a ligature mark that matched the position of the body.6 She argued Birchmore had depression and other risk factors for suicide, and said Farwell told investigators he went to the apartment to break up with her and told her the baby was not his.6 She said a defense expert will testify that little force is needed to break the hyoid bone, and that DNA evidence excluded Farwell from both of Birchmore’s hands.6 A court filing says DNA testing showed Farwell was not the father of the child.731
Oct. 13. A Stoughton police detective who had known Birchmore through the Explorers testified that she did not believe Birchmore was suicidal; the defense questioned how well she knew her.7 The principal of the school where Birchmore worked as an instructional assistant testified that she was excited about the pregnancy and last worked on Feb. 1, 2021; on cross-examination the defense brought out that she had told students her police-officer boyfriend was the father, and that her pay had been docked for excess sick days.7
Oct. 14. State Police Trooper Matthew Dunne, who worked the original death investigation, testified that the death was not initially treated as suspicious, that a broken pendant necklace was missed and found later by a relative, and that his Feb. 6, 2021 interview of Farwell in a parking lot was not recorded, which he called a “tactical decision.”8 On cross-examination he testified that he saw no signs of forced entry or a struggle and no sign the body had been moved, that no suicide note was found, and that there were no cameras at the apartment door or stairwell to show when Farwell left.8 He also testified that coworkers said Birchmore had talked about anxiety and possible depression, that a relative had reported a mental-health diagnosis and a past hospitalization, and that a January 2021 prescription for the antidepressant Zoloft was found in the apartment.8 A State Police crime lab toxicologist testified that no alcohol or common drugs of abuse were found, and that sertraline (Zoloft) was detected.89 A Stoughton police sergeant testified that he had never known Birchmore to be suicidal and that he and Farwell attended a State Police homicide conference in 2019.89
Oct. 15. The sergeant testified that Farwell seemed “stressed” in late 2020 and early 2021, and that Farwell’s wearing a mask in the building video was “very odd” because he opposed mask rules; on cross-examination he said he knew Birchmore only superficially.10 A friend of Birchmore’s testified that Birchmore told her Farwell shoved her to the ground after she asked him to sign a birth certificate, that she spoke to Birchmore on the phone on Feb. 1 and noticed nothing unusual, and that she went to Canton police after the death and urged them to investigate Farwell.10 Stoughton’s police chief testified that she did not know of the Jan. 20, 2021 call until the FBI told her in spring 2024, and that officers may not have sex on shift.10 A digital forensic analyst testified that a search of Farwell’s iPhone found no messages with Birchmore’s number, and on cross-examination acknowledged that some laptop files were lost during review.10 The former deputy chief who led the department’s internal investigation testified that he did not know of the sexual relationship before her death and that the recording of the Jan. 20 call was automatically purged.10
Oct. 16. The former deputy chief testified on cross-examination that the Jan. 20 call involved a hypothetical question about an extramarital affair and did not mention a minor.12 An FBI digital forensic examiner testified that about 24,000 recovered communications were between Birchmore and Farwell, that a device linked to Farwell’s email searched “can you revoke consent in massachusetts” on Feb. 9, 2021, and that a list of baby names Birchmore made days before her death included “Matthew.”1211 On cross-examination he confirmed that she searched earlier on Feb. 1 for the color of a suicide-awareness ribbon and sent messages referring to self-harm or suicidal thoughts.11 FBI Special Agent Heidi Kelsch testified that the FBI took the case in October 2023, read Birchmore’s side of text exchanges while a prosecutor read Farwell’s, and said of the alleged 2013 conduct, “She was too young to consent.”1113 She testified that Farwell sent Birchmore messages telling her to delete their messages.13 She was still on the stand when court recessed for the weekend.12
Oct. 19. Kelsch testified that Birchmore texted Farwell in December 2020, “Congrats, we are going to be parents in 2021,” and that in October 2020 Birchmore had threatened to expose the relationship unless he agreed to give her a baby.14 She testified that in January 2021, after the call to the Stoughton department, Farwell asked Birchmore for a key to her apartment and offered to help raise the baby if she kept the relationship secret.14 On cross-examination she testified that a paternity test identified another man as the father, and acknowledged that Birchmore had discussed a previous suicide attempt; the defense showed the jury journal entries, messages and an Instagram image it said reflected suicidal thoughts and distress.14
Oct. 20. Birchmore’s obstetrician testified that a Jan. 18, 2021 ultrasound showed a viable pregnancy, that she considered it a “high-risk pregnancy” because of what she described as undertreated mental-health issues, and that she was surprised to learn the death had been ruled a suicide.15 On cross-examination she testified that her 2019 records noted past thoughts of self-harm and prior diagnoses of depression and anxiety, and that she relies on patients to report their histories accurately.15 Finishing about nine hours on the stand, Kelsch testified on cross-examination that a necklace seen in crime-scene photos was never collected.15 A former Stoughton police dispatcher testified that he took the Jan. 20, 2021 call, that Farwell reacted with anger when told of it and told him not to discuss it, and that Farwell texted him that night telling him never to discuss it again; on cross-examination he said he did not recall the caller reporting a crime or mentioning a relationship with a minor.15 A family-law attorney testified that Birchmore consulted her in 2020 and early 2021 about pregnancy-related family law and visitation rights.15
Oct. 21. A State Police forensic scientist described receiving the ligature, clothing and other samples and sending them for DNA testing.16 A psychologist who studies childhood sexual abuse described stages of grooming; she testified that she had not reviewed case documents or interviewed witnesses.16 A friend testified that Birchmore told her Farwell was “aggressive towards her stomach” during sex after learning of the pregnancy.16 A Stoughton detective testified that in late January 2021 Farwell told her a woman was threatening to reveal an affair and that he “believed the problem was going to take care of itself.”16 Another detective testified that Farwell seemed “frantic” when asked about a rumored relationship with Birchmore on Feb. 7, 2021.16 Birchmore’s hairdresser testified that Birchmore told her the relationship began when she was 13; on cross-examination she did not recall whether she had told investigators that.16
Oct. 22. The man DNA testing identified as the father of Birchmore’s unborn child testified under a grant of immunity, and the judge instructed jurors on how to weigh it.1917 He testified that he and Birchmore began a sexual relationship in December 2019, that she told him Farwell had been her first sexual partner when she was 15 or 16 and that he encouraged her to report it, and that she insisted Farwell was the father; he said he gave the FBI a DNA sample in June 2025 and later learned he was the father.1719 He testified that she never showed signs of self-harm or suicidal thoughts; on cross-examination the defense questioned him about a text in which Birchmore asked whether he would keep “our secrets,” and he denied that she ever told him he might be the father.1720 A State Police DNA analyst testified that DNA on the ligature was a mixture from four contributors that included Farwell’s and Birchmore’s, and that Farwell was excluded from DNA under Birchmore’s fingernails.1718 On cross-examination she said she could not testify about DNA transfer and that she interpreted the test results but did not perform the testing.1718 Three women testified that they had sexual relationships with Farwell in 2012 and 2016.19 A friend of Birchmore’s testified that Birchmore told her Farwell said he hoped she would die or kill herself after learning of the pregnancy, and that she did not believe the death was a suicide; on cross-examination she confirmed telling investigators that Birchmore “would tell different stories to different people.”1718
Oct. 23. Birchmore’s longtime mental-health counselor testified that Birchmore was a “fighter” who struggled with anxiety and grief before her death but was not suicidal; she was to return to the stand Oct. 26.21
Oct. 26. Dr. María Del Mar Capó-Martínez, the state pathologist who performed the autopsy, testified that police told her the death was a suicide, that no one initially asked her to consider homicide, and that she had not seen the building video, the phone data or witness statements when she made her 2021 ruling.2322 She testified that she changed the manner of death to undetermined in April 2026 after learning more about the case, that she was not pressured to do so, and that she could not recall another broken hyoid bone in a woman under 30 who died hanging in a seated position.23 On cross-examination she confirmed that Smock had shared his view that the death was not a suicide at a 2024 meeting with FBI investigators, before she changed her ruling, and the defense suggested the hyoid could have been affected by the position of the head in the days before the body was found.23 Farwell’s twin brother then began testifying under a grant of immunity from the Justice Department; he testified that he too had sex with Birchmore while on duty as a Stoughton officer.2223
Oct. 27. The twin brother testified that the brothers never discussed Birchmore while she was alive, that in a 2021 call his brother denied having sex with her before she was 16, and that Birchmore told him she was pregnant with his brother’s child and “seemed happy.”23 On cross-examination the defense suggested he was angry at his brother over the loss of his own job; he said, “I am not upset with my brother about that.”23 Smock testified that Birchmore was a “victim of a homicidal act,” that investigators had visited an “altered crime scene,” and that he would not expect a broken hyoid in a 23-year-old who died in that position; he called her hair tangled in the strap a “huge red flag.”23 On cross-examination the defense noted that he is not a board-certified forensic pathologist.23
Oct. 28. Digital forensics examiner Jessica Hyde, the government’s last witness, testified that Birchmore’s phone last locked at 9:13 p.m. on Feb. 1, 2021, a minute before Farwell is seen entering the building, and that its last recorded action, a button press, was at 9:40 p.m., about two minutes before he is seen leaving.2524 The prosecution rested after her cross-examination.24 The defense’s first witness, a Massasoit Community College administrator who supervised Birchmore as a peer tutor, testified that in 2017 she told him she had tried to kill herself that weekend, and that he wrote a report about it.2425
Oct. 29. A former boyfriend from 2016 testified for the defense that Birchmore talked about suicide but, to his knowledge, never attempted it, and that she kept journal pages listing reasons and methods for suicide as well as reasons not to die.2627 On cross-examination the prosecution brought out that she had once told him she would leave a suicide note; none was found in 2021.27 Chief Medical Examiner Mindy Hull testified that individual medical examiners decide which specimens to preserve and that she was present when the hyoid bone was removed from its preservative.26 A medical examiner’s office technician who removed the body testified that the call came in as a “suspected suicide” and that she did not notice or collect the broken necklace.2627
Oct. 30. Dr. Melissa Piasecki, a psychiatrist called by the defense who did not treat Birchmore but reviewed her records, testified that Birchmore had multiple suicide risk factors that “add up and accumulate,” including childhood adversity and isolation, and that a breakup with Farwell “would have been very overwhelming” for her.28 On cross-examination she agreed that victims of child sexual abuse sometimes form attachments to their abusers, and acknowledged that Birchmore did not search for ways to die or send suicide-related messages on Feb. 1, 2021; on redirect she said Birchmore had a detailed, hopeful vision of the pregnancy.28
Farwell, 40 at the time of trial, is married and a father of three.317 He has a twin brother, who testified at the trial under a grant of immunity.3823 Stoughton’s police chief testified that she knew him when he was himself a teenage member of the Explorers.10
According to the indictment, he volunteered with the Explorers before 2012 and became an instructor when he joined the Stoughton Police Department that year.4 He rose to detective and served as president of the patrolmen’s union, the Boston Globe reported.38 He was placed on paid administrative leave a few weeks after Birchmore’s death and resigned in April 2022.38 In March 2024 he agreed to voluntary decertification by the state’s Peace Officer Standards and Training Commission, which had accused him of a sexual relationship with Birchmore beginning when she was 15 and of lying to State Police; he said he “made no admission of wrongdoing.”39
Birchmore was raised by her mother and grandmother, who both died in 2016, according to the Globe.38 She graduated from Stoughton High School in 2015 and completed studies at Massasoit Community College in 2018, the Globe reported.38 A Stoughton police sergeant who met her through the Explorers when she was about 11 or 12 described her as “incredibly impressionable” and said she admired police and military personnel.8
No testimony, finding or on-record statement about Farwell’s mental health was found in the sources reviewed.
Farwell has been held since his arrest in August 2024 and remained in federal custody when the superseding indictment was returned.375 He has not testified, and no public statement by him about the charges was found in the sources reviewed, beyond his denial of wrongdoing in the decertification agreement and his not-guilty pleas.39
Prosecutors allege Farwell, who met Birchmore through the Stoughton Police Explorers youth program, began sexually abusing her when she was 15, and strangled her on Feb. 1, 2021, then staged a suicide to keep her from reporting him.34 "He killed her so that she couldn't talk about what he had done to her or with her," prosecutor Torey Cummings told the jury.6 They point to a fractured hyoid bone and other injuries that their forensic expert says show homicide.26
"Matthew Farwell did not kill Sandra Birchmore. He did not," defense attorney Kimberly Stevens told the jury.67 The defense does not deny the affair but argues Birchmore died by suicide after Farwell ended the relationship, notes that the state medical examiner ruled her death a suicide, and says Farwell never believed the baby was his; a court filing says DNA testing showed he was not the father, and another man testified that testing identified him as the father.763119 The defense has suggested that federal prosecutors pressured the medical examiner to revise her ruling, the Boston Globe reported.21 The pathologist testified that she was not pressured to change it.23
Surveillance video shows Farwell entering Birchmore's Canton apartment building that evening and leaving 29 minutes later, according to an FBI affidavit.2
Birchmore is found dead in her apartment.38
A state medical examiner rules the death a suicide by hanging.2
Farwell agrees to voluntary decertification by the state police oversight commission, without admitting wrongdoing.39
Farwell is arrested on a federal indictment charging him with killing a witness or victim.3
A superseding indictment adds a charge of causing the death of her unborn child.45
Prosecutors give notice that they will not seek the death penalty.35
The state medical examiner's office has amended the death certificate, changing the manner of death from suicide to undetermined.33
Judge Casper denies the defense's renewed request to move the trial out of Massachusetts.32
Jury selection begins in federal court in Boston.30
Opening statements.6
The prosecution calls its first witnesses; an FBI special agent is still testifying at the end of the week.712
The second week of testimony; on Oct. 22 the man identified as the child's father and a State Police DNA analyst testify.141718
The pathologist who performed the autopsy, Farwell's twin brother and the government's forensic expert testify.2322
The prosecution rests, and the defense calls its first witness.2425
The trial resumed Nov. 2, 2026, with defense testimony expected through Wednesday, Nov. 4; closing arguments could follow, and deliberations could begin by the end of that week, the Boston Globe reported.29 Witnesses the defense said it would call include a forensic anthropologist expected to testify about the force needed to break a hyoid bone, and Dr. Thomas Andrew, a former New Hampshire chief medical examiner who reviewed the autopsy and could not rule out suicide.29 Whether Farwell will testify had not been reported. Count One carries a mandatory life sentence on conviction.57