A 17-year-old boy from Saga Prefecture currently in police custody for allegedly hijacking a bus and fatally stabbing a passenger has told investigators that he thought the 1999 massacre at a Colorado high school was "cool."

Investigative sources said the youth, whose name is being withheld due to his age, appeared to take great interest in the April attack on Columbine High School, in which two students killed 13 and injured 23 before taking their own lives.

The Saga teen also reportedly expressed his admiration for the perpetrators of the 1995 sarin gas attack on the Tokyo subway system. He allegedly carried on about the Aum Shinrikyo religious cult, saying he was moved by the sheer scale of the attack.

Authorities believe that the boy, whose grudge against his family and society allegedly grew after he dropped out of high school, was fascinated by crime and came upon the idea of committing a criminal act himself.

According to investigators, the youth has cited such motives as "I wanted to make a display before society by doing something big." and "I want to correct society."

Yet the boy fails to give answers when investigators ask specific questions, they said.

The boy allegedly also said he had planned to attack his former junior high school the day after he was admitted to a national institute for psychiatric treatment on March 5.

During their investigation, police discovered that the boy had searched the Internet, including one home page carrying details of the 1997 serial child murders in Kobe, to satisfy his curiosity about crime.

He also reportedly said that he felt outwitted when he learned of the murder of a housewife in Toyokawa, Aichi Prefecture, allegedly committed by another 17-year-old. boy, just days before the hijacking.