I would argue temp insanity, seeing your children die before your eyes; it is very understandable how it could make anyone lose it.
Several years ago, I can recall a father that shot the man that kidnapped and raped his son. There was even a video of the scum bag being lead by some marshalls and the father, shooting the guy dead. He was not convicted
Nemo ME Impune Lacessit
Manus sapiens potens est