The death of a 3-month-old baby who was severely beaten last week has been ruled a homicide, the medical examiner said Thursday.

The girl, Sherlin Camacho, died in the hospital on Monday after she was taken off life support, her mother’s attorney said. The medical examiner said the cause of death was blunt force injury to the head.

Camacho was first rushed to the hospital on Tuesday after her father found her not breathing inside their West Farms apartment on Honeywell Avenue, near East 181st Street, according to police and Jessica Cuadrado, her mother’s attorney.

The baby’s mother, Katherine Plasencia, had just fed the infant and left for work before she stopped breathing, Cuadrado said.

When her father, Manuel Camacho, found Sherlin, he asked their roommate to call 911, Cuadrado said. When police arrived, they tried to perform CPR on the girl.

“They’re devastated,” Cuadrado said, adding that when the parents arrived at the hospital “they went up to her room and she was already off the machines.”

No arrests had been made as of Thursday morning.

Following the incident, the couple’s 5-year-old son was interviewed by investigators with NYPD doctors and officials from the Administration for Children’s Services present, Cuadrado said.

During the interview, she said, he indicated he got angry when his sister cried and acted aggressively toward a doll when asked about his sister. But Cuadrado said Plasencia, who is 23 years old and works at a phone store, doesn’t believe he is capable of violence.

The boy is now in the custody of a relative. There was no prior history of ACS involvement, Cuadrado said.

“These are great parents,” she added.

A representative for ACS said the agency is “saddened by this troubling news and are investigating the circumstances leading to this child fatality, along with the NYPD.”

-With Nicole Brown