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CASE PRIMER · BACKGROUND
U.S. v. Farwell, explained
A young woman found dead in her apartment, a death first ruled a suicide, and a former police officer now charged in federal court with killing a witness. Here's who everyone is and how the case got to where it is, before you open the case file.
TIMELINE OF EVENTS · THE FACTS
MAR 2010 · AGE 12
Sandra joins the Stoughton Police Explorers
Birchmore, then 12, applies to the Stoughton Police Explorers Academy — a vocational program for local youth — and begins that spring, remaining through about 2016.
2012
Farwell becomes an Explorers instructor
A former Explorers volunteer, Farwell joins the Stoughton Police Department in 2012 and serves as an instructor in the youth program — a position of trust over its teenage participants.
BEFORE AGE 16 · ALLEGED
Farwell begins sexually abusing Birchmore
The indictment alleges Farwell engaged in sexual intercourse and other sex acts with Birchmore before she turned 16, and that the sexual contact continued until early 2021.
DEC 2020 · AGE 23
Birchmore learns she is pregnant
Birchmore learns she is pregnant and tells Farwell that he is the father of the child.
JAN 20, 2021 · ALLEGED
A tip reaches Stoughton police
According to the indictment, a friend of Birchmore calls the Stoughton Police Department to report that Farwell had been having sex with her; a department employee then tells Farwell about the call.
FEB 1, 2021 · AGE 23 · ALLEGED
Birchmore is killed; the scene is staged
Prosecutors allege Farwell strangled Birchmore — then eight to ten weeks pregnant — and staged her Canton apartment to make her death appear a suicide.
AUG 2024 → OCT 2025
Federal charges and superseding indictment
Farwell is charged federally in 2024; a 2025 superseding indictment charges him with killing a witness and with causing the death of an unborn child. He has pleaded not guilty and is held pending trial.
Full case timeline
HOW THE CASE FITS TOGETHER
FEDERAL · PRETRIAL
D. Mass.
U.S. v. Matthew Farwell
The active prosecution. Farwell, a former Stoughton officer, faces a federal charge of killing a witness in connection with Birchmore's death. He has pleaded not guilty and is detained pending trial.
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THE UNDERLYING DEATH
Canton, MA
The death of Sandra Birchmore
First reported as a suicide in February 2021, later reclassified as a homicide after the file was reopened. That reversal is what turned a closed case into a federal prosecution.
TERMS WORTH KNOWING
Killing a witness
A federal offense targeting the death of someone to prevent their testimony or cooperation. It is why the case is in federal, not state, court.
Reclassification
The formal change of a death's manner — here, from suicide to homicide — after new review. It reopened an investigation many assumed was over.
Detained pending trial
A court order holding a defendant in custody until trial, rather than releasing them on bail. Farwell has been held since his 2024 arraignment.
Discovery
The pretrial phase in which the parties exchange evidence, including any disputes over expert testimony about the cause and manner of Birchmore's death.
WHO'S WHO
MF
Matthew Farwell
A former Stoughton police officer, now the defendant. Charged federally with killing a witness; has pleaded not guilty and is detained pending trial.
SB
Sandra Birchmore
The 23-year-old found dead in Canton in 2021. She had known Stoughton officers for years through a department youth program.
DOJ
Federal prosecutors
The U.S. Attorney's Office for the District of Massachusetts, bringing the case in federal court on the witness-killing charge.
CT
The District Court
The U.S. District Court for the District of Massachusetts, which will set the trial date and rule on pretrial motions.
WHY IT MATTERS
A death once closed as a suicide became a federal homicide case against a former officer. How it is tried — and how the reversal is explained — will shape public trust in how these deaths are first investigated.
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