Updated

Two girls provided high school officials with a tip that led police to charge four boys with planning a lunch-period massacre, the school's interim principal said.

Authorities have said the boys — ages 14 to 16 — planned to attack students, teachers and others at Winslow Township High. Their names were not released because of their ages.

Interim Principal Michele Ferner said she first learned of the alleged plot on March 30, when the girls visited her in her office and mentioned a 2003 movie that depicts a school shooting.

"The kids trusted the administration and the teaching staff enough to come to us with the rumors, knowing that we would investigate them," Ferner told the Courier-Post of Cherry Hill.

The boys were arrested Wednesday and face charges of murder conspiracy, terrorism, terroristic threats, and conspiracy to make terroristic threats.

The father of one of the boys has said the charges were a mistake.