A passer-by sounded the alarm to police at 12.30am on Saturday when they saw smoke billowing out from under a block of flats on Brantholmsgränd in the Stockholm suburb of Skärholmen.
There were several cars in the garage, two of which were on fire. With the fires extinguished, the emergency services were able to confirm that they had found a dead body in one of the vehicles.
The body had not been identified early on Saturday morning and police have not ruled out murder.
“We don’t know if this concerns a murder, a suicide or an accident,” said Linda Feldt at south Stockholm police to news agency TT.
The burned out car in which the body was found did not have any registration plates.
Police have sealed off the area around the scene to conduct a forensic examination.
The suburb of Skärholmen has been the scene of several car fires in recent weeks but police do not believe that there is a connection to this case.