RIVERTON, Kan. – 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. Norman said he would ask prosecutors to bring charges of conspiracy to commit murder against the teens, ages 16 to 18. 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. 160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set! AD Quality Auto 360p 720p 1080p Top articles1/5READ MOREOregon Ducks football players get stuck on Disney ride during Rose Bowl eventOfficials at Riverton High School began investigating on Tuesday after learning that a threatening message had been posted on MySpace.com. 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.