A 38-year-old former Massachusetts detective was charged by federal prosecutors with grooming and later murdering a pregnant 23-year-old woman, according to the Department of Justice (DOJ).

Matthew Farwell, the accused cop, allegedly strangled Sandra Birchmore to death around Feb. 1, 2021 and staged the murder to make it appear as if she committed suicide, a DOJ press release states. (RELATED: Police Officer Indicted In Fatal Shooting Of Pregnant Woman)

Birchmore joined a Stoughton Police Department (SPD) youth program in 2010, according to the DOJ. Farwell joined the SPD around March 27, 2012 During that time. The former cop allegedly began a sexual relationship with Birchmore was 15-years-old.

Farwell was 27 at the time he began a sexual relationship with her, according to the indictment, ABC News reported. The affair lasted until her death, prosecutors allege, according to the DOJ.

“Farwell allegedly used his authority and access to groom, sexually exploit and ultimately sexually abuse” Birchmore, the DOJ added.

Former cop accused of killing pregnant woman, staging death to look like suicide https://t.co/ZYMYWcaWJG

— ABC7 Eyewitness News (@ABC7) August 29, 2024

“We allege that Sandra Birchmore survived years of grooming, statutory rape and then sexual violence all at the hands of Matthew Farwell, who was employed throughout their relationship as an officer and then detective with the Stoughton Police Department. And when it became clear to Mr. Farwell that he could no longer control Ms. Birchmore, he silenced her permanently,” acting U.S. Attorney Joshua Levy told the press Wednesday, ABC News reported.

Farwell was married and had children during the course of the alleged affair, prosecutors reportedly said. Prosecutors claimed that the pair “reached an agreement” back in October 2020 when she allegedly told Farwell that she wanted him to impregnate her “in exchange for her silence about his criminal conduct (i.e., child sexual abuse) and years-long extramarital affair,” according to the outlet.

When she told Farwell she was pregnant and wanted him to be involved in the child’s life, he allegedly became enraged and physically abusive toward her, according to the DOJ. “At one point while she was pregnant, Farwell allegedly held Birchmore in a headlock and told her that he wished she were dead,” the DOJ writes.

A friend of Birchmore’s called the SPD in late January 2021 and disclosed the two’s affair, the DOJ alleges. Farwell allegedly learned about the call and became “visibly angry” about it as well as Birchmore telling friends he had been violent toward her, Levy claimed, ABC News reported.

Farwell directed Birchmore to destroy evidence of their relationship, court documents reportedly alleged. He later allegedly strangled her to death with a duffle bag strap, according to the outlet.

Farwell pleaded not guilty to the charges during a Wednesday court appearance, The Sun reported. If Farwell is convicted, he could face life in prison or the death penalty, ABC News noted. Levy reportedly said the DOJ has yet to decide on pursuing the latter sentence.