Photo/Illutration Hidemitsu Matsumoto is escorted from a police station to the prosecutors’ office on suspicion of fatally attacking a renowned blogger in Fukuoka in June 2018. (Asahi Shimbun file photo)

FUKUOKA--The Fukuoka District Court handed an 18-year prison sentence to a man who fatally stabbed a renowned blogger during a lecture visit to this city last year.

Prosecutors had sought a 20-year-term for the defendant, 43-year-old Fukuoka resident Hidemitsu Matsumoto.

Matsumoto was quoted by police after his arrest as saying that he held a grudge against Kenichi Okamoto, 41.

The feud was apparently over posts written by Okamoto under his handle Hagex. In them, he condemned an infamous Internet troll, believed to be Matsumoto, for "repeatedly posting slanderous remarks online."

Hagex was well-known in the online world.

A focus of contention during the trial was whether Matsumoto had the capacity to take responsibility for his crime.

The defense team, citing a developmental difficulty Matsumoto had been diagnosed with, argued that his responsibility was limited, as he had a diminished capacity at the time of the attack.

Presiding Judge Tadayuki Okazaki, however, ruled otherwise, explaining: "It was a premeditated act based on a firm intention to kill. As for his motive, it was outrageous and self-centered."

According to prosecutors, Matsumoto repeatedly stabbed Okamoto in the neck, chest and back on June 24, 2018, causing his death.

Okamoto worked for a Tokyo-based cybersecurity firm and was visiting Fukuoka to give a talk at a business start-up support center in the city.

Matsumoto ambushed Okamoto when the latter entered the men's restroom after giving a talk.

Matsumoto fled the scene, but later turned himself in to police.