No psychological test will allow you to state that your group recruits is free of the week individuals and freaks.
Soldiers raping and killing are as old as civilization but the difference between an army and a horde is how they get punished.
While I recognize that we are only being fed the "anti-military" feed from MSM, I do hope that the crime was made up but if it happened the way it is being portrayed, there was not only one crazed psycopath, there were a bunch of them and this would not be their only crime.