TOKYO, June 9, 2008 (AFP) A disturbed young auto worker who killed seven people on a stabbing frenzy in downtown Tokyo had advertised what he was going to do on an Internet bulletin board, police said Monday.

As stunned mourners placed flowers, sweets and comic-book images at a makeshift shrine, new details emerged of how he kept a detailed log of his plans to wreak havoc in Akihabara, the hub of Tokyos comic-book subculture.

The assailant behind Japans deadliest crime in seven years, 25-year-old Tomohiro Kato, worked on a temporary contract at an auto components factory in central Shizuoka prefecture, police said.

On Sunday, he drove a rented two-tonne truck some 100 kilometres from the town of Susano to Tokyo, swerving the vehicle into pedestrians before bursting out and stabbing at random with a survival knife.

He told police he was “tired of living” and had no motive other than to kill people -- anyone he found.

Kato reportedly had a strong interest in comic-book and video-game subculture.

In a school yearbook in which graduating students were asked to describe their personalities, Kato enclosed a picture of an action hero and simply wrote the word “crooked” in English, reports said.

He admitted to police that he documented his journey on Internet bulletin boards posted from his mobile telephone, a police official said.

“Ill crash my vehicle into people and if the vehicle becomes useless, Ill get out a knife. Goodbye everyone!” said one posting hours before the crime. On a different site, an anonymous posting on May 27 was entitled “A disaster in Akihabara” and warned that an incident would take place imminently.

Kanto Auto Works, the company to which Kato was dispatched from a temping agency in November, said that he had been working normally until going missing from the workplace on Friday. “Weve been told that his attitude at work was very good and that he didnt stir any problems in the workplace,” said company spokesman Naoyuki Hashimoto.

Residents of Katos hometown interviewed by Nippon Television said that he did well at school. “He was good both at studying and sports. He was respected in the classroom,” one woman said.

Around the crime scene, overnight rain had washed away the bloodstains from the streets of the electronics district, where residents placed flowers and pressed their hands in prayer at a makeshift shrine set amid the neon signs.