Police are conducting interviews Thursday in an effort to determine whether charges will be filed against a couple who prayed rather than seeking medical help for their 11-year-old daughter, who died Sunday from a treatable diabetic condition.

"We certainly believe that even though they firmly believed in their faith that they have a responsibility to provide medical attention for their daughter," Everest Metro Police Chief Dan Vergin told FOX News.

An autopsy concluded that Madeline Neumann of Weston, Wis., died Sunday from diabetic ketoacidosis, an ailment that left her with too little insulin in her body. Investigators said she probably had been ill for about 30 days, suffering from symptoms such as nausea, vomiting, excessive thirst, loss of appetite and weakness.

"I believe that they did know she was ill, especially in the last week or so," Vergin said. "We know that the mother had communicated with her sister-in-law and others, and so certainly they had known she was ill and getting worse each day as this disease progressed."

Leilani Neumann, Madeline's mother, told the Associated Press that she never expected her daughter to die.

"We just noticed a tiredness within the past two weeks," Neumann said. "And then just the day before and that day [she died], it suddenly just went to a more serious situation. We stayed fast in prayer then. We believed that she would recover. We saw signs that to us, it looked like she was recovering."

Wisconsin Social Services has interviewed the family's three other children — ages 13, 14 and 17 — and had them examined by a medical doctor, Vergin said. They will most likely be returned to the home.

It will be up to the district attorney to decide whether or not to file charges against Madeline's parents, Vergin said.

"The parents certainly didn't want their daughter to die, they didn't want her to be ill," Vergin said. "They just chose a course of action that allowed her to regress into coma and then death."

The Associated Press contributed to this report.