Police have changed their narrative about the sudden death of toddler siblings in New York last week.

Olivia Gee, 2, and Michael Gee, 3, died three minutes apart early Monday morning, after their mother’s boyfriend reportedly found them in their beds struggling to breathe. Both children suffered severe asthma, and the Daily News reports that their mother, a nurse practitioner, administered medication intended to open the air passages before calling 911.

An hour later, both children had died.

Initially, doctors told police they believed both children has succumbed to asthma attacks, and bruising around their necks may have been caused by CPR. But a medical examination of the toddler girl’s body indicated that she was a victim of an assault to her abdomen and upper body.

“It looks like this girl was punched in the stomach. It’s a homicide investigation,” a law-enforcement source told the New York Post.

The Daily News reports that her death is likely to be ruled a homicide. Her brother Michael’s autopsy is scheduled for Tuesday.

Police reportedly questioned Novell Jordon, 31, the boyfriend of the toddler’s mother Jade Spencer, “deep into the night” on Monday. But he has since been released without charges.

On Tuesday, police removed a computer from the Bronx apartment.

When a Daily News reporter went to the apartment, someone inside shouted that no one was available to speak.

Jade Spencer is reportedly devastated by the deaths of her children, and required medical attention after being informed they had passed away.

This is a developing story and will be updated as more information becomes available.

Feature photo: Facebook