Updated

A family court judge ordered $500,000 bond on Monday for each of three 15-year-old boys accused of plotting to kill two specific people and anyone else in their way on the first day of class at their suburban New Orleans school.

That first day went quietly at Lakeshore High School, though there were more uniformed deputies than usual keeping an eye out.

The cash bond ordered by Judge Mary Devereux of St. Tammany Parish means the boys' families must turn over the entire amount to the court to guarantee the teens' appearance, rather than paying a bond company 10 percent of the total.

Devereux imposed a gag order on all other details of the case against the three students at Lakeshore High School, said Rick Wood, spokesman for 22nd District Attorney Walter Reed.

"She pointed out clearly in court it was a half-million dollars cash bond. That's all I can tell you," Wood said.

The teens were arrested last week and held at a juvenile detention center on charges of conspiracy to commit terrorism.

Sheriff Jack Strain said Friday that they apparently spent the summer making detailed plans to shoot a student, a faculty member, and police. His spokesman, Capt. George Bonnett, said indiscriminate shooting also was in the plot. The students planned to finish with suicide, Strain said Friday.

Because the boys are juveniles, their names have not been released. Strain said none had an arrest record that he knew of. Conviction on the conspiracy charge could keep them in detention until they turn 21, Bonnett said.

On Monday he said the judge's gag order barred him from describing extra security measures at Lakeside and other parish schools.

"The judge specifically brought us in and limited us to speaking about three items," he said — the fact that there was a hearing, the amount of the cash bond, and "when and if any of them do post bond."

Newspaper, television and radio reporters said there were several armed deputies around the campus.

St. Tammany Parish Schools Superintendent Trey Folse said he did not visit the school or know how many extra deputies joined the usual security officer. About 800 students — including the first senior class for the school that opened in 2009 — went to classses, he said. The school had more than 600 students in grades 9-11 last year.

"I thought it was best to stay out of the way and let the principal run his school," Folse said. "Other people showing up would have been just a distraction to him and the kids."