Three of the victims were children
The fire in Lake City started sometime before 1:45 a.m. Tuesday and was discovered by a police officer on patrol.
The state fire marshal's office says three children and one adult were killed. Lake City Police Chief Bobby Rist says one of his officers noticed smoke coming from the south edge of town. The officer followed the smoke to the house and found it engulfed in flames.
Rist says the smoke and flames prevented the officer from getting into the house. Investigators say the fire is not considered suspicious, but the cause is being investigated.
Lake City is a town of about 1,700 residents that sits about 75 miles northwest of Des Moines.