Akihabara has been a popular spot both for locals and tourists looking for bargains on the latest appliances and computers. In the past few years, Akihabara started to draw more crowds who wish to have coffee or tea at "maids cafes" where waitresses dressed in French maids' costumes serve them. The area is also a "must-go" for Japanese "anime" fans visiting stores selling comics and figures of various anime characters.
"He probably did not care whether he was arrested or not as a result of his act," said Nobuo Komiya, a professor of criminology at Rissho University in Tokyo. "He had so much anger he had to let it out. It could be toward people or it could be toward society."
Earlier this month, Kato posted a series of cell phone messages onine suggesting his loneliness.
Date: May 21 Time: 19:34 "Is there anyone who needs me? I can tell for a fact that there is not."
Date: May 22 Time: 19:19 "I had to work late. I am drinking alone eating a packed meal from a convenience store. I am alive because I do not have the courage to kill myself."
Kato reportedly told the police he was dissatisfied with his work and work environment. His employer told reporters that Kato reported to work three days before the attack. He said Kato screamed and dashed out of the factory, as he said his work clothes were missing. Kato never returned.
Although Kato would write his comments to the online community, he sometimes felt "no one understood him," according to the police.
Date: June 1 Time: 03:11 "Everyone should die."
Date: June 1 Time: 07:06 "Murder should become legal."
"The act of killing probably was a form of revenge for him," said Komiya. "Committing a crime of such a large scale might have been his way of being not ignored."
Japan has seen an increase in murders of strangers in recent years. In 2006, there were four of such crimes, which doubled the following year.
This year, there already have been five cases where innocent bystanders were killed. In March, a 24-year-old man killed one person in southern Japan and killed another and injured seven in central Japan.
Also in March, an 18-year-old male pushed an office worker off a train platform. The male worker was run over by a train and died. None of the victims knew the suspects, who told the police they "did not care" who they killed.
"People who are unhappy in life somehow take their anger out on people," said Masayuki Kiryu, a professor of criminal psychology at Kansai University of International Studies.
"People used to take things out on objects such as kicking a vending machine when they were outraged. But some people now use people as objects to release their anger, which is quite chilling."
Kiryu said society in general is guarded today, and it has less tolerance for ambiguity. "As a result, we tend to kick out people who may not fit in. Many parents tell their kids not to talk to strangers. That may help in terms of self protection, but that also deprives people of communication. They do not learn how to talk to people directly."
There have been at least three warnings posted on the Internet in the last eight years, which resulted in actual murders. Prime Minister Yasuo Fukuda asked authorities to look into external factors that may prompt young people to commit heartless crimes.