The suspect has denied the allegations, according to sources familiar with the investigation.

The arrest was made after his wife was found dead in the kitchen of the house at around 9:10 a.m. on Tuesday, when the couple's nine-year-old son, Ryosuke, and six-year-old daughter, Miyu, were also found dead in the bedroom on the second floor.

Nakata has told the police that he has no idea about the children's deaths, the sources said.

At a press conference following the arrest, Fukuoka police executives expressed a deep apology to the public. "We take this seriously and will work to restore public trust," Makoto Hisata, administration chief at the Fukuoka police department, said. (Jiji press)