The 15-year-old boys, who called themselves Day Zero, identified a student and a faculty member whom they planned to kill, Sheriff Jack Strain said in a conference call with reporters Friday. They also planned indiscriminate shooting, as well as firing at any sheriff's deputies or other officers they saw and taking their weapons, said Capt. George Bonnett, a spokesman for the sheriff.
"Like many other cases similar to this, they fully intended to end this episode with taking their own lives," the sheriff said.
Schools start Monday in St. Tammany Parish. Schools Superintendent Trey Folse said other students at Lakeshore High School told school officials about the plan on July 17, and the officials immediately notified him and the sheriff's office.
"These kids ... were planning to carry out an incredible and devastating attack on a school. To me, the bigger story is this office worked with school authorities to make sure this didn't occur," Strain said.
Principals talk at least once a week with sheriff's office supervisors and Folse talks at least once a week with him, Strain said.
Most schools stepped up security in the aftermath of the 1999 tragedy at Columbine High School near Denver, Colorado, where two students fatally shot 13 people and themselves.
The three teenage suspects were being held at a juvenile detention center on charges of conspiracy to commit terrorism and more charges were possible, the sheriff said. Conviction on the conspiracy charge could keep them in detention until they turn 21, Bonnett said.
"They made no attempt to deny their involvement with the plan and admitted their intentions," police said in a news release. "All three were cooperative with investigators."
Strain said he did not know whether the students had problems at school. He said he did not know of any prior arrest record.
Because the boys are juveniles, their names have not been released by authorities. Strain said he did not know if they had attorneys.
Judging from the amount of material confiscated and the detail of the plans, Strain said, the boys apparently had been planning the attack throughout the summer. He didn't know if the targets were chosen because of something that happened last school year.
He would not say whether they already had guns or where they planned to get them, nor would he comment about a possible motive. But Bonnet said it wasn't race, because the arrested boys are of different races.
Strain also didn't know whether Day Zero might have had more than three members, adding, "But from every shred of evidence we have collected and every shred of intelligence we have been able to garner, we don't believe there were any other participants" in the alleged plot.
The boys turned themselves in this week. A bond hearing Monday will decide if they can leave the detention center.
Strain said extra deputies are always posted around schools on the first day of classes, and Monday will be "all of that and then some ... Steps most parents will readily notice, and steps that not even students will see."
He quickly added of the enhanced security, "I don't want anyone to think this will happen one day and then it will be over."
He wouldn't give details.
One of the boys is from the Mandeville area, an affluent bedroom community about 25 miles north of New Orleans where the school is located. The other two were from nearby Lacombe, a slightly less affluent and rural area.
Folse said he did not know how many students reported the threat or how worried they were. "It alerted them enough to turn it over to authorities, with trust that the people they alerted would look into it and take it seriously."
"I'm very proud of them for stepping up and doing the right thing," Folse said.