The U.S. attorney's office says the suspects used peer-to-peer networks to exchange graphic images and videos, then stored the files on their computers.
The majority of students described their typical episode of suicidal thinking as intense and brief -- more than half the episodes lasting one day or less.
The father of the two youngest children, admitted he pitted the children against each other, giving them plastic baseball bats and other weapons and encouraging them to fight, police said.