Police arrested a 76-year-old former top bureaucrat of the farm ministry on Saturday over the alleged murder of his son at their home in Tokyo.

Hideaki Kumazawa, also a former ambassador to the Czech Republic, was arrested at the scene after the police received a call from him saying he had stabbed his son to death, according to investigators. His 44-year-old son, Eiichiro, was confirmed dead after being taken to a hospital.

Kumazawa, who lived with his wife and Eiichiro, has admitted to stabbing his son with a kitchen knife, according to investigators.

A police source quoted Kumazawa as saying his son confined himself at home and rarely went out.

The younger Kumazawa also “used violence at home,” police quoted the father as saying. Police believe troubles within the family prompted the suspected to kill his son.

After arriving at the scene, a police officer found the collapsed victim bleeding from the chest. The wife was absent when police officers arrived at the home.

The son was lying on a bloody futon mat, and police believe the suspect stabbed the victim while he was on the mat.

“I think (the family) moved here about 10 years ago, but I have never seen the son,” said an 86-year-old man who lives in the neighborhood and was astounded to hear the news of the murder.

The house is located within a quite residential area, about 650 meters south of Heiwadai Station on the Yurakucho subway line.

Kumazawa, a graduate of the University of Tokyo who joined the predecessor of the Ministry of Agriculture, Farm, Forestry and Fisheries in 1967, became the ministry’s top bureaucrat in 2001.

He stepped down the following year amid criticism of the ministry’s handling of a mad cow disease outbreak.

He served as Japan’s ambassador to the Czech Republic from 2005 to 2008.