The incident occurred in a private house in the village of Mezenskoye, Zarechny urban district.
The fire killed a man and two children, and injured two adults and three children.
“A criminal case has been initiated on the grounds of a crime under part 3 of article 109 of the Criminal Code of Russia (infliction of death by negligence on two or more persons),” RIA Novosti quotes a message from the Investigative Committee.
Investigators are considering several versions, including violation of the rules for the operation of furnace equipment and careless handling of fire.
Earlier, a fire broke out in a trade and exhibition center in the Tyumen region.