The bodies of six people were found in the remains of a three-story house that burned down early Friday morning in the city of Shizuoka, police said.
The fire, which broke out around 2:40 a.m., spread to four homes nearby. No neighbors were injured.
It took 90 minutes to put out the blaze.
Police suspect the deceased were members of the family of the owner of the house, who was identified as Masami Endo, 69, a tailor who suffered serious injuries and was hospitalized.