CALGARY -- Police say they expect to lay murder charges against the parents of a 15-year-old boy who died from diabetes complications.

Investigators in Calgary said Tuesday that the couple did not provide proper medical treatment for their son.

Police allege that the boy was diagnosed with Type 1 diabetes several years ago, when the family lived in British Columbia, and his parents had been taught how to treat him with insulin. When his health declined, investigators say he was confined to his room.

Police were called to a home in Calgary last May and found his body.

Staff Sgt. Grant Miller with the homicide unit wouldn't provide details of the boy's condition when he was discovered, but described it as "extreme."

"This boy has suffered from long-term neglect to the point that he was unable to seek medical attention on his own," Miller said.

"When you care for a loved one or a child and they're sick, you need to take them to the doctor."

He said tests later revealed the teen died of a bacterial infection stemming from neglect and starvation due to his diabetes.

Miller wouldn't say how long the boy was sick, but said he was being home-schooled and did not have a family doctor in Alberta. Social workers in Alberta weren't involved with the family, he said.

"They do not have a lot of contact with people in the community and the public at large, so that's why I think this could have gone on for as long as it did."

Investigators are looking at different theories as to why the parents didn't seek medical help, said Miller. He said police spoke with different religious groups the family was involved with and ruled out religion as a motive.

"In fact, it was people from one of those groups that urged this family to eventually call for an ambulance for this boy," Miller said.

The parents have seven other children. Most are adults. Miller said there is no evidence they were neglected.

"This boy was not cared for and others in the family received more care."

Police planned to release the names later Tuesday, when the parents were to be formally charged before a justice of the peace.