Read The Evil That Men Do Storyline:
Buffy faces her greatest challenge - human evil, without the supernatural element.When a normal, smart, well-balanced student suddenly shoots his family and then himself, Buffy and her gang figure one of the usual suspects -- vampires, demons, or witches -- must be responsible. But when it seems that everyday stuff like drugs, peer pressure, and thwarted love are to blame, Buffy decides to dig a little deeper just to be sure.
Pages of The Evil That Men Do :