Updated

Five teenage boys accused of plotting a shooting rampage at their high school on the anniversary of the Columbine massacre were arrested Thursday after a message authorities said warned of a gun attack appeared on the Web site MySpace.com.

Sheriff's deputies found guns, ammunition, knives and coded messages in the bedroom of one suspect, Sheriff Steve Norman said. Authorities also found documents about firearms and references to Armageddon in two suspects' school lockers.

"What the resounding theme is: They were actually going to do this," Norman said.

Norman said he would ask prosecutors to bring charges of conspiracy to commit murder against the teens, ages 16 to 18. Attorney General Phill Kline said in a news release that his office was taking over the prosecution at the request of the Cherokee County attorney.

Deputies' interviews with the suspects indicated they planned to wear black trench coats and disable the school's camera system before starting the attack between noon and 1 p.m. Thursday, Norman said. The suspects apparently had been plotting since the beginning of the school year.

Officials at Riverton High School began investigating on Tuesday after learning that a threatening message had been posted on MySpace.com, he said.

The message discussed the significance of April 20, which is Adolf Hitler's birthday and the anniversary of the 1999 Columbine High School attack in Colorado, in which two students wearing trench coats killed 13 people and committed suicide, the sheriff said.

"The message, it was brief, but it stated that there was going to be a shooting at the Riverton school and that people should wear bulletproof vests and flak jackets," Norman said.

School officials identified the student who posted the message and talked to several of his friends, Norman said.

But Riverton school district Superintendent David Walters said the significance of the threat didn't become clear until Wednesday night, after a woman in North Carolina who had chatted with one of the suspects on Myspace.com received more specific information that there would be about a dozen potential victims, at least one of whom was a staff member. She notified authorities in her state, who contacted the sheriff's department, Norman said.

Norman said that the potential victims were popular students and that the suspects may have been bullied.

"I think there was probably some bullying, name calling, chastising," he said. He also said investigators had learned the suspects were computer buffs who liked violent video games.

About 900 students in all grades go to school on the campus.

Riverton is an unincorporated area of about 600 people along what once was the famed Route 66 in southeast Kansas, near the Oklahoma and Missouri borders.

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