Prosecutors said the victim and defendant had argued online before meeting for the first time outside Park Street station.

BOSTON, Mass. — A Dorchester woman was sentenced to 15 to 20 years in prison after pleading guilty to manslaughter in the 2023 stabbing death of 21-year-old Jazreanna Sheppard outside the Park Street MBTA station, bringing a sudden end to a case that had been headed to trial.

The sentence closed a prosecution built around witness accounts, surveillance footage and records of hostile social media exchanges that prosecutors said turned deadly when Alyssa Partsch confronted Sheppard with a knife in downtown Boston. The case drew attention because the women had never met in person before that night, and because Sheppard left behind a young child whose future was invoked repeatedly in court.

By the time Partsch stood before Superior Court Judge Mary Ames on April 1, the case had already changed course. Trial was scheduled to begin later in April, but Partsch instead admitted guilt to manslaughter, a lesser offense than the second-degree murder charge she had faced since 2023. Ames then imposed a state-prison term of 15 to 20 years. The courtroom discussion reached back to the night of July 20, 2023, when Sheppard was with a friend near Brewer Fountain in Boston Common shortly before 11:30 p.m. As the pair headed toward the Park Street MBTA pavilion, prosecutors said, Partsch approached. Video later reviewed by investigators showed a fight, and prosecutors said Partsch stabbed Sheppard multiple times in the face, head and torso before fleeing through the transit system. Boston police officers responded around 11:34 p.m. to the area of 121 Tremont St. and found Sheppard badly wounded.

Emergency crews took Sheppard to a hospital in critical condition, but she later died from her injuries. The prosecution said the encounter did not come out of nowhere. According to the Suffolk County District Attorney’s Office, witness testimony and documentary evidence showed that Partsch and Sheppard had been trading hostile messages online before July 20 and that Partsch had threatened Sheppard and tried to draw her into a fight. Officials said the women had not met face to face before the stabbing. That claim became one of the most striking details in the case: a conflict that had played out on screens moved into one of Boston’s busiest public spaces and became fatal within moments. Partsch left the scene after the attack, prosecutors said, and investigators later pieced together the confrontation using witness statements and video evidence. Authorities arrested her months later, at about 6 a.m. on Nov. 4, 2023, in Dorchester.

The long gap between the stabbing and the arrest gave the case a second timeline, one shaped by investigation rather than violence. Boston police said Partsch was taken into custody on a murder warrant in the area of 25 Wainwright St. after homicide investigators reviewed the facts and circumstances of the case. Publicly, officials disclosed little at the time beyond the basic account that a young woman had been stabbed near Park Street station and later died. In court and in later releases, prosecutors filled in the rest: the meeting near Boston Common, the prior online hostility, the knife attack, the flight through the MBTA system. The location mattered. Park Street is one of the city’s central transit hubs, where Boston Common, Tremont Street and subway traffic come together. The fatal confrontation unfolded at the edge of a place known more for commuters and tourists than for a planned encounter between two people who had been feuding online.

The legal path also shifted sharply. Partsch was originally charged with second-degree murder, a charge that would have put the case before a jury had it gone to trial. Instead, she pleaded guilty to manslaughter just weeks before jurors were expected to be seated. Prosecutors did not publicly lay out in detail why they accepted the plea, but the result was immediate: no trial, no witness testimony before a jury and no contested verdict. What remained was sentencing, victim impact statements and the court’s final account of what the case had cost. Ames addressed Partsch directly, saying the killing was senseless and telling her she hoped Partsch now understood the consequences for Sheppard’s family. The judge’s remarks focused not only on the death itself but on the child who would grow up knowing his mother through relatives and memories. District Attorney Kevin Hayden later called the killing a senseless, impossible-to-understand act of violence.

Family members gave the hearing its emotional center. Relatives described Sheppard as a deeply loved person whose care reached outward to the people around her. Their statements stood in contrast to the stark language of the court record, which reduced the case to dates, charges and injuries. In the courtroom, Sheppard was remembered instead as a daughter, cousin and mother. Hayden said the family’s words were heart-rending, and Ames echoed their loss in her own remarks before imposing sentence. The hearing did not answer every question. Officials have not publicly released the full content of the social media exchanges or a fuller account of what was said between the women in the seconds before the fight turned deadly. But the broad shape of the case is no longer in dispute: an online feud, a first in-person meeting, a knife attack outside a central subway station and a prison sentence handed down nearly three years later.

The case now stands closed in Superior Court unless future appeals or post-conviction filings emerge, and the clearest remaining milestone is the sentence itself: 15 to 20 years for a killing the judge said left a family to carry forward the memory of a young mother.

Author note: Last updated April 23, 2026.