The alarm was first raised at 1.13am and by the time the fire services arrived at the scene the house was completely on fire.
Four people, two adults and two children, were taken by ambulance to the university hospital in Örebro. They were all family of the dead boy.
According to a report from the hospital, two people had “mild burns” and were moved out of intensive care during the day.
On Monday afternoon the police and fire experts investigated the remains of the family home.
“The cause of the fire is still unclear,” said Torbjörn Carlsson, the press officer at Örebro police, to TT.
“We have not had any proper discussions with the people who were in the property and we know very little about the chain of events themselves.”