Southington (AP) — The death of a 19-year-old woman in an apartment fire in Southington has been ruled a homicide, the state Chief Medical Examiner's Office said Monday.

The agency determined that Kristen Milano died of smoke inhalation in Sunday's blaze at the Summer Brook Apartments. Authorities, however, would not say why they thought Milano's death was a homicide.

The cause of the fire remained under investigation. Police declined to comment on witness reports saying the fire may have been started by someone who threw a firecracker. No arrests have been announced.

Milano was found in a second-floor bedroom while two of her relatives managed to escape.

Fire officials say the blaze began at about 4:30 a.m. Sunday in the apartment where Milano was living. Firefighters from nearby towns responded to help local authorities.

"Firefighters made it to the second floor and were confronted with high heat, punishing conditions, and found her in one of the bedrooms," Fire Lt. Glenn Dube told WFSB-TV.

Relatives said the two people who escaped the fire apparently didn't know that Milano had returned home the night before.

"I know when they talk about heartache, but it feels like my heart was in a vice and just got crushed. It's terrible," Milano's father, Michael Milano, told WTNH-TV.