CLEARWATER, Fla. (WFLA) – It’s a case that has Clearwater detectives heartbroken, as they investigate the tragic death of a little boy, allegedly killed at the hands of his father’s girlfriend, Shantay Belcher.

The child was just 7 years old and, in the last hours of his life, authorities say was suffering and alone. Police say Belcher and her own three children were in the next room the whole time.

“It’s a very sad thing,” explained Lt. Michael Walek. “Very difficult when you’re talking about a child who is 7 years old who won’t be able to go outside and play anymore, or play football or do things that he loves.”

The mom was arrested Sunday night. Police say she admitted she knew something was wrong right from the start and she should have called 911.

According to an arrest report, the boy fell asleep on his bedroom floor around 8:30 p.m. on Saturday. Belcher told police she was unable to wake up him, so detectives said she left him there. The report says her own son told her the boy was “gasping” for air.

“The first thing you would do is render aid and ensure that child’s safety and well being,” said Lt. Walek.

Detectives say the mom made her own 10-year-old son help drag the boy’s body into a bathtub of cold water where she left him for nearly ten hours until Sunday morning, documents show. Police said she did not call 911 until the father came home shortly after.

The little boy was rushed to Morton Plant Hospital and pronounced dead.

Detectives are now waiting for an autopsy to be completed. The mother is currently being charged with child neglect.

However, according to police, those charges could change once the autopsy results come back.