A mother and her two elementary school children were found dead Tuesday in their home in Ogori, Fukuoka Prefecture, and the Fukuoka Prefectural Police said Wednesday they have started a murder investigation.

According to the police, 38-year-old Yukiko Nakata was found lying on the kitchen floor on the first floor of her house and her 9-year-old son, Ryosuke, and 6-year-old daughter, Miyu, were discovered in the bedroom upstairs. All three had apparently been strangled, they said.

On Wednesday, the police found a burned charcoal briquette near the mother's body, leading them to believe that someone might have tried to make the scene look like a murder-suicide. Yukiko's husband, who is a police officer with the prefectural police, told investigators that the three were asleep when he left for work at around 6:45 a.m. Tuesday. Later in the morning, when he was informed that his children had not come to school, he asked Yukiko's sister, who lives nearby, to check on the house.