The ruling came nearly two weeks after police made the grim discovery inside the Mattapan residence.
According to investigators, officers with the Boston Police Department responded to an unusual report on July 18 after an individual walked into the District E-18 police station and informed officers that someone had been shot.
Police were dispatched to the property, entered the residence, and carried out what officials described as a protective sweep.
Inside a second-floor apartment near a rear bedroom, officers located Ocasio’s body.
Emergency responders pronounced the 18-year-old dead at the scene.
Medical examiners conducted an autopsy the following day and determined that she had suffered a single gunshot wound to the head.
At the time, officials listed the cause of death but withheld a final ruling on the manner of death while additional forensic work was completed.
That process concluded Thursday when investigators officially determined the death was a homicide.
Despite the ruling, the investigation remains active.
Authorities have not announced any arrests, identified any suspects, or filed criminal charges.
Boston Police Department detectives assigned to the Homicide Unit continue to investigate exactly what occurred inside the home.
The property where the killing occurred has also become part of the public discussion because ownership records identify Conan Harris, the husband of Rep. Ayanna Pressley, as the owner.
The two-story residence, originally built in 1910, contains seven bedrooms and has operated as a rental property.
Public records indicate the home carries an assessed value of roughly $919,000 and had recently been placed on the market with an asking price of approximately $1.15 million.
Law enforcement officials, however, have moved quickly to separate the property owners from the investigation.
Police stated there is “absolutely nothing that indicates any connection to the owners of the property.”
Pressley’s congressional office also responded after news of the tragedy became public.
“The Congresswoman extends her deepest condolences to the impacted family,” a spokesperson for Pressley’s office said shortly after the body was found.
The spokesperson further confirmed that neither the Massachusetts congresswoman nor members of her family had any involvement in the incident.
Pressley later expressed sorrow over the tragedy, saying she was devastated by the young woman’s death and noting that Ocasio’s life had been cut tragically short.
Meanwhile, Ocasio’s family has spoken publicly about their loss.
Her mother, Elenie Ocasio, identified her daughter in the days following the discovery and said she believes the killing stemmed from domestic violence.
She has also publicly stated that she believes she knows who is responsible for her daughter’s death.
In a GoFundMe campaign established to help cover funeral expenses, Elenie Ocasio described her daughter as “deeply loved by her family, friends, and everyone whose life she touched” and mourned the loss of “someone so young, with so many dreams, hopes, and milestones still ahead of her.”
She also issued a heartbreaking statement about her daughter’s final moments.
“This coward killed my baby. He put a gun to her head, took my baby in that house and left her to die.”
Although the victim’s mother believes domestic violence played a role, investigators have not publicly confirmed that theory.
Officials likewise have not identified any person of interest or announced whether anyone is being sought in connection with the case.
For now, detectives continue gathering evidence as they work to determine who was responsible for the killing.
The investigation remains ongoing, and Boston authorities have indicated they will release additional information if and when new developments emerge.
