An elderly couple and their two grandsons were killed earlier this week in a fire that gutted their house in Kawatana, Nagasaki Prefecture, police said Wednesday.

The police identified the couple as Hisao Kanaya, 74, and his wife, Tomie, 70, but were unable to find the bodies of Hiroya Shigemoto, 5, and Takumi Shigemoto, 3, both from nearby Kumamoto Prefecture, until Wednesday morning. The fire occurred at 7:50 p.m. Tuesday, they said.

The police said they will conduct autopsies on the children to verify their identities.

At the time of the fire the couple's daughters, aged 36 and 24, were out shopping, according to police investigations. The elder daughter is the mother of the two boys.

The Shigemotos had been staying at the Kanayas' home since Thursday for the Bon summer holidays.