One teenager pleaded guilty and another was expected to do the same Thursday to their roles in a foiled plot to go on a shooting rampage that was to begin at their Camden County high school.

The alleged ringleader, Edwin DeLeon, 15, waived his case from juvenile to adult court and was scheduled to enter a guilty plea there Thursday afternoon.

Under a deal with authorities, he would be sentenced to no more than six years in state prison for conspiring to possess a firearm for an unlawful purpose, said Bill Shralow, a spokesman for the Camden County prosecutor's office.

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Authorities have said the Winslow Township boy had been plotting for months to get a gun and, with the help of friends, shoot at students and teachers in the school, as well as residents of the community. But no violence took place and the boys did not have weapons, authorities said.

The boys were arrested in April after the principal at Winslow Township High School heard about the alleged plot.

Also Thursday, a second 15-year-old from Winslow, whose name has not been released publicly because of his age, pleaded guilty as a juvenile to charges of conspiracy to possess a firearm for an unlawful purpose. He agreed to serve up to three years in a juvenile detention facility. His sentencing is scheduled for Sept. 28.

He also pleaded guilty to simple assault in an unrelated case and could face up to six additional months in custody for that charge.

A third boy, Peter Cunningham, 16, pleaded guilty last month to conspiracy to possess a firearm. He was to serve no more than five years in state prison.

One case remains unresolved. A 15-year-old from nearby Hammonton was scheduled to be in court on Aug. 17. Unlike the other boys, who have remained in detention, he has been under house arrest. His lawyer has denied that the boy took part in the plot and said he believed the plans were a joke.