Five teenagers suspected of plotting a shooting rampage at their high school will stay in custody through the weekend while prosecutors decide whether to file charges, a judge ruled Saturday.

The boys ages 16 to 18 were arrested Thursday, the anniversary of the Columbine massacre, after school officials learned that a threatening message had been posted on MySpace.com, authorities said.

District Judge Robert Fleming signed an affidavit Saturday that said there was probable cause to believe a crime was committed, said Kansas Attorney General Phill Kline.

Under Kansas law, the students would have been released if Fleming had not signed the affidavit by Saturday morning, Kline said.

Kline said he will determine early this coming week whether to file criminal charges and whether to have the four juveniles tried as adults.

"We're going to try to get charges filed as soon as we can get it together," Kline said.

Bail was set at $500,000 for each of the teens. Their next bail hearing was set for Monday.

Cherokee County Sheriff Steve Norman said the teens planned to disable the school's security camera system before staging their attack Thursday. Sheriff's deputies found guns, ammunition, knives and coded messages in the bedroom of one suspect and documents about firearms and references to Armageddon in two suspects' school lockers.

MySpace.com — a social networking hub with more 72 million members — issued a statement saying it wouldn't discuss the case because of the investigation, and added that it has set up mechanisms for users to report inappropriate content.

Riverton is a community of about 600 people in southeast Kansas, near the Oklahoma and Missouri lines.