No one was hurt by the device, comprised of Drano and aluminum foil in a plastic bottle, found last week, The Charlotte (N.C.) Observer reported Tuesday.
Bud Cesena, Charlotte-Mecklenburg Schools' police chief, said the teen suspects, at least most of whom are soccer players at Butler High, allegedly had planned to put the bottle bomb at the home of a girlfriend and only placed it in the Butler teacher's mailbox after being scared off. They apparently didn't know a teacher lived at the residence, Cesena said.
"I feel pretty good that they were just stupid," Cesena said.
The chief added that the type of bomb made was not as dangerous as one using gasoline or gunpowder, but has been known to produce shrapnel.
"Depending on the amount of product you use, it can be very, very dangerous," Cesena said.
Ryan McIntyre, 18, and Nicholas Fichman, 16, were both charged with misdemeanor criminal property damage for allegedly damaging the inside of the mailbox. The other students were not identified because they had not been charged.
Police were looking into whether or not a Butler High faculty member had been a part of the scheme, as a parent of a soccer player said the teenagers were talking about the prank after practice and showed their coach the bomb materials.