A 1-year-old Bronx girl who was rushed to the hospital in critical condition late last month died Friday, and police said they are investigating her death as a homicide.

NYPD officers found 1-year-old Imani Mitchell semi-conscious at a building on Union Avenue and East 152 Street in Melrose after responding to a 911 call around 9:30 p.m. on Aug. 28, according to police officials. She was taken to Harlem Hospital and last Friday succumbed to severe brain injuries, police said.

Officials said Sunday her death was ruled a homicide.

On Aug. 29, a day after Mitchell was hospitalized, police said they arrested her mother’s boyfriend, 19-year-old Jerome Thomas, and charged him with two counts of assault and endangering the welfare of a child. They said he lived at the same address where Mitchell was found in distress.

According to a criminal complaint filed by the Bronx district attorney, Mitchell’s mother left her in Thomas’ care for less than an hour on the night of Aug. 28. When the mother returned home, the complaint states, Mitchell was in bed with bruising on her head and having difficulty breathing.

Thomas said he hit Mitchell twice with a “heavy hand,” causing her to cry, according to the complaint. She was admitted to the neurointensive care unit at NewYork-Presbyterian/Columbia University Medical Center, where the document states she was put on a ventilator and doctors removed part of her skull to try to relieve pressure in her brain.

Police officials said Monday additional charges were expected in the case, following Mitchell’s death. Thomas’ attorney did not respond to a request for comment. The defendant is due back in court next week, records show.

NYPD data through August shows homicides in the 40th Precinct, which includes Melrose, were down by two compared to the same period last year. Citywide they decreased about 20%, according to the data.

This is a developing story based on preliminary information from police and has been updated with additional details.