TOKYO: Yasuyuki Deguchi, a Tokyo criminologist, said Satoshi Uematsu’s actions were typical of someone who bears a grudge and seeks revenge, because it appeared he planned out the attack, and then he turned himself in to the police.

“Accomplishing his goal was all he wanted,” Deguchi said on TV Asahi.

Michael Gillan Peckitt, a lecturer in clinical philosophy at Osaka University in central Japan, and an expert on disabled people’s issues in Japan, said the attack speaks more about Uematsu than the treatment of the disabled in Japan.

“It highlights the need for an early-intervention system in the Japanese mental health system. Someone doesn’t get to that state without some symptoms of mental illness,” he said.

Mass killings are rare in Japan. Because of the country’s extremely strict gun-control laws, any attacker usually resorts to stabbings. In 2008, seven people were killed by a man who slammed a truck into a crowd of people in central Tokyo’s Akihabara electronics district and then stabbed passers-by.

In 2001, a man killed eight children and injured 13 others in a knife attack at an elementary school in the city of Osaka. The incident shocked Japan and led to increased security at schools.

As recent as earlier this month, a man stabbed four people at a library in northeastern Japan, allegedly over their improper handling of his questions, although no one died.

In 2010, 14 were injured by an unemployed man who stabbed and beat up passengers on two public buses outside a Japanese train station in Ibaraki Prefecture, about 40 kilometres northeast of Tokyo.