Authorities said Tuesday they so far see nothing suspicious about a house fire in northwestern Minnesota that killed a toddler and critically injured his mother.

The blaze struck the house about 9 miles northeast of Detroit Lakes in the 23000 block of Duffney Road about 12:45 a.m. Sunday.

The body of Micah Hedlund, 2, was located in the home, which was fully engulfed in flames, read a statement from Becker County Sheriff’ Todd Glander.

His mother, 46-year-old Melissa Hedlund, remains hospitalized at HCMC in Minneapolis in critical condition, said hospital spokeswoman Christine Hill. Hedlund is suffering from smoke inhalation and burns, the Sheriff’s Office said.

Also hospitalized are her husband, 48-year-old Michael Hedlund, and a 5-year-old girl. Their conditions were not immediately available.

Glander said “there is nothing at this point” to suggest that the fire was suspicious in nature. He also said investigators “have an idea” about where in the home the blaze began, but he declined to say more.

Children in the basement heard smoke alarms, saw flames on the main floor and alerted family members, who escaped, the Sheriff’s Office said.

Michael Hedlund and one of the 2-year-old’s older siblings went back in to search for the boy but were unable to find him, the Sheriff’s Office added.