To most of Japan, the deadly stabbings in Tokyo were an incomprehensible act of sudden and indiscriminate violence.
But to readers of an obscure Web site called "Extreme Exchange, Revised," the attack in a popular shopping district that left seven dead Sunday was foretold.
The suspect sent messages saying he wanted to kill somebody, anybody, and apparently hoped to be stopped. But his words were lost in a million postings.
Police refused to comment on how, or when, they learned of Tomohiro Kato's postings. But Japanese news reports Thursday said the suspect told prosecutors under questioning that he deliberately hinted at his bloody plans on the Internet in the hope someone would see them and stop him.
Kato's Internet activity
Within hours of his arrest, news of Kato's Internet activity began to surface and access to the Extreme Exchange site — the bulletin board to which Kato sent postings from his cell phone — was quickly restricted by the site operator.
The Associated Press obtained access to a mirror site — a copy of the original site captured before it was shut down and posted on another server. In it, Kato's postings offer a wealth of insight into his pre-attack mind-set. They were generally listed only by number, with no name or even nickname attached.
As early as two months ago, Kato laid out his basic plan of attack, though he added at the time that he wouldn't carry it out.
Then, as though writing a live feed, on the day of the killings he posted some 30 times, saying he was on his way to the Akihabara area, that he intended to kill and, finally, just 20 minutes before the rampage began, that "it's time."
Kato, a 25-year-old factory worker, is accused of ramming a rented 2-ton truck into a crowd of pedestrians at the popular shopping area and then racing around wildly with a military-style dagger and stabbing as many people he could before police finally overpowered him on a side street.
The assault lasted only a few minutes, but when it was over seven people lay dead in pools of blood and another 10 had been wounded in the worst attack on the streets of Tokyo since the Aum Shinrikyo doomsday cult unleashed nerve gas on the subway system in 1995.
Kato was arrested at the scene with his bloodstained weapon, and police say he has confessed. Under the Japanese legal system, prosecutors have 20 days to formally charge him.
Internet his 'only refuge'
To anyone who would read his ramblings, Kato complained for months that he was ugly and would never find a girlfriend, that he felt he had no future and — increasingly toward the end — that he just wanted to kill somebody, anybody.
The Internet, he wrote, was his "only refuge."
But even there, his voice was drowned out.
The Extreme Exchange bulletin board Kato posted to was a small feature in a larger site called Megaview — which gets more than a million posts a day. Users needed only to register to post, with no fee. The chatter on the various Megaview boards ranges widely, but is mostly innocuous and terse — thus making it all the less likely to raise any red flags.
Megaview's operator was not immediately available for comment.
The case comes as Japanese authorities have been increasingly concerned about Internet abuse, often involving suicidal posters and people chillingly spurring them on:
- Last October, police arrested a man who ran an Internet site on which he offered himself as a murderer-for-hire. The 33-year-old electrician allegedly gave a 21-year-old suicidal woman sleeping pills and suffocated her in April. She paid him $1,700.
- In December, four young Japanese men were found dead inside a sealed car with a charcoal stove inside. Charcoal stoves, which emit carbon monoxide fumes that cause asphyxia, are frequently used in group suicides in Japan. Police believe the men met on an Internet chat site designed to bring suicidal people together.
- Last month, some 50 Japanese reportedly killed themselves by mixing household chemicals to produce the deadly gas hydrogen sulfide, prompting Japan's National Police Agency to urge Internet providers to delete materials from Web sites showing readers how to mix the chemicals. Some sites reportedly provide "poison gas" warnings that viewers can print out and hang outside their doors when they kill themselves.
Experts believe there is also a great deal of criminal activity out there — from drug dealing to prostitution to casing houses for burglaries — and point to Extreme Exchange as an example of what the authorities are up against.
Internet postings difficult to monitor
Yoshiaki Ishii, an official in charge of Internet guidelines at the Ministry of Internal Affairs and Communications, said anyone can set up a bulletin board and start a "thread" on just about any topic, from harmless observations to the solicitation of criminal activities.
He said that because of the sheer volume of Internet chatter, it is virtually impossible to monitor the ravings of users who may or may not make the transition from venting their rage into the ether to actually manifesting it violently on the streets.
Sites and their users are notoriously fluid and hard to keep track of. Users are often anonymous or posting under false names and sometimes under elaborately conceived false identities.
The government has set up a four-member task force in cooperation with four major umbrella organizations of 300 Internet providers and site operators to step up their policing on the Web, according to Hiroyuki Kuwako, of the Telecom Services Association, who is one of the four members.
Kuwako confirmed to the AP that Kato had posted on the Extreme Exchange board, but said that only came to the attention of the authorities afterward. He stressed that the task of monitoring such postings to prevent crime is Herculean.
"We cannot be monitoring every single site 24 hours a day, and policing the sites also encounters an issue of freedom of speech," he said. "The postings in the latest case were found in hindsight."
Experts note that though Kato's violent outburst has dominated the nation's attention, his underlying rage may be shared by many more young Japanese who live alone and face increasing economic and social insecurity as Japan's society changes.
Spending an increasing amount of time online, instead of with friends or family, these young people are also more likely to seek consolation in Internet chat rooms than in real conversations, often increasing — not easing — their feelings of isolation.
"There are many people who have troubles and have nobody to turn to other than strangers on the Net," said Kuwako. "In the end, we just have to hope that other Internet users can give a helping hand to save a suicidal message sender or others who are proposing a crime."