Police have charged the mother of a seven-year-old boy, believed to have drowned in a south Edmonton apartment Tuesday, with first-degree murder.

Nerlin Lizbeth Sarmiento, 32, is scheduled to make her first court appearance Friday.

"We firmly believe we have enough evidence to show the death was premeditated," Staff Sgt. Bill Clark of the Edmonton Police Service homicide section said in a news release.

Omar Aileen Jajoy lived with his parents and older sister in the apartment at 109th Street and 53rd Avenue.

The boy was taken to hospital after he was found inside the Chateau Apartments in the Pleasantview neighbourhood around 8:30 a.m.

He was pronounced dead shortly after arrival.

"It has destroyed the family," police spokeswoman Clair Seyler said Wednesday.

Court records show Sarmiento has no prior criminal record.

Neighbour Ping Xiong lives just down the hall from the family, who are originally from Colombia. She said that Omar was polite and always with his sister.

"Very nice boy," she said.

She said Sarmiento worked part-time at Superstore grocery store and she spoke to her just a few days ago.

"I said, oh it's a little bit boring over here. And she said yes. So I think she's a little bit lonely."

Social workers and grief counsellors attended the boy's south Edmonton school Wednesday morning.

Edmonton Public Schools spokeswoman Jane Stirling said a letter was sent home with students explaining the situation.

"It's certainly very unique in the fact of the way the young boy lost his life," she said.

"It's usually involving an accident or a child's been ill and it's a little bit easier to share that information."