The defense team of a former top bureaucrat appealed Wednesday a court ruling last week that sentenced him to six years in prison for murdering his socially reclusive son.

The appeal was filed with the Tokyo High Court five days after Hideaki Kumazawa, the 76-year-old former vice minister for agriculture, forestry and fisheries, was released on ¥5 million bail.

The Dec. 17 ruling by the Tokyo District Court determined the defendant repeatedly stabbed his 44-year-old son Eiichiro in the neck and chest on June 1 at their home in Tokyo, leading to his death from massive blood loss.

The defense had sought a suspended sentence. It claimed Kumazawa had long supported his eldest son, who had a developmental disorder, and that Eiichiro's violent temper at home was the catalyst for the murder. Prosecutors had sought an eight-year term.

While acknowledging some of the defense's claim, the court determined Kumazawa had a "strong intention to kill," as there were more than 30 wounds found on his son's body.

The case has drawn considerable public attention due to the large number of social recluses, known as hikikomori, age 40 to 64 in Japan, with the government putting the figure at around 613,000 across the country.

The high court, in a rare decision, granted bail to the defendant even though he was sentenced to jail for the murder. It is believed the court took into account Kumazawa's age and his guilty plea.