Former detective accused of killing pregnant woman he had sexual relationship with when she was underage

STOUGHTON, Mass. (TCN) -- Federal prosecutors indicted a former detective this week for allegedly killing a pregnant woman and staging it like a suicide to prevent her from revealing information about their sexual relationship, which began when she was underage.

The U.S. Attorney’s Office for the District of Massachusetts announced Wednesday, Aug. 28, that 38-year-old Matthew Farwell was arrested and charged with one count of killing a witness or victim in connection with the strangulation death of 20-year-old Sandra Birchmore.

According to the U.S. Attorney’s office, in 2010, when she was 12 years old, Birchmore joined a local program called the Stoughton Police Explorers Academy because she was interested in working in law enforcement. Farwell worked as an instructor in the program and allegedly "used his authority and access to groom, sexually exploit, and ultimately, sexually abuse Birchmore."

The abuse allegedly began when she was 15 and continued for several years. The affidavit says Farwell was 27 years old when they allegedly began their affair. Farwell and Birchmore allegedly sometimes had sex when he was on duty as a detective with the Stoughton Police Department. The statement alleges Farewell concealed his actions by claiming he worked certain hours even though he was not actually on duty.

Birchmore found out in December 2020 that she was pregnant. She reportedly was "excited about the pregnancy" and started buying different child care items and "telling loved ones how happy she was to become a mother." Birchmore reportedly informed Farwell that he was the father and she "expected him to be involved" in their child’s life.

According to the statement, Farwell allegedly became violent with her when she brought up the pregnancy. One time, he allegedly put her in a headlock and "told her that he wished she were dead."

On Jan. 20, 2021, one of Birchmore’s friends contacted the Stoughton Police Department and reported Farwell and Birchmore’s relationship. Farwell found out and sent Birchmore text messages about it. A few days after the call, Farwell reportedly asked Birchmore for a spare key to her apartment.

Birchmore was last seen alive on Feb. 1, 2021, at 5:33 p.m. walking outside her apartment with a snow brush. Farwell texted her at 9:08 p.m. and asked her if he could "come by for a second." She responded that the door would open. The affidavit says surveillance video captured Farwell walking into Birchmore’s building wearing a sweatshirt with the hood up and a face mask, which was allegedly unusual for Farwell because several people told investigators Farwell "resisted wearing a mask during the pandemic."

Farwell was seen leaving the apartment at 9:43 p.m.

Birchmore’s co-worker contacted the Canton Police Department on Feb. 4, 2021, and requested a welfare check because Birchmore did not come to work that day. Police entered her apartment and discovered Birchmore "seated on the floor in a reclined position with a duffle bag strap tied around her neck."

The strap was attached to a doorknob.

One of the first responders at the scene reportedly said Birchmore had been dead for "days."

Data from her phone showed no movement or activity since Feb. 1, 2021, at around 9:18 p.m.

The medical examiner initially ruled Birchmore’s death a suicide. Investigators, however, noted that her actions in the days leading up to and day of her death was "inconsistent" with someone "choosing to die by suicide that day."

The affidavit alleges Farwell lied to investigators about the last time he had sex with Birchmore. He reportedly did not "express any sadness, grief, or remorse about Birchmore’s death."

The U.S. Attorney’s office alleges Farwell "killed Birchmore with the intent to prevent law enforcement from learning about Farwell’s commission or possible commission of federal offenses."

If convicted, Farwell could be sentenced to life in prison or be given the death penalty.

Stoughton Police Chief Donna McNamara said in a statement, "The alleged murder of Sandra is a horrific injustice. The allegations against the suspect, a former Stoughton Police Officer, represent the single worst act of not just professional misconduct but indeed human indecency that I have observed in a nearly three-decade career in law enforcement."

McNamara went on, "It has been my life’s work over these past three years to ensure that justice was served. As I have stated previously, Sandra Birchmore received no justice during her life. It is imperative that justice be served in her death, and today’s actions appear to bring our society one step closer to justice."

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