Two people believed to be father and son died in a fire early Monday at their home in Yukuhashi, Fukuoka Prefecture, police said.
The victims are believed to be Kiyomi Anraku, 49, and his 13-year-old son, Kazuaki, they said.
Anraku's 16-year-old daughter broke her left ankle after jumping from the second floor to escape, and Anraku's father, 79, sustained minor injuries, police said.
His wife, 47, found their house burning when she returned from work, they said.