Saitama Chainsaw Shoujo

From Horobi no Michi:Kirisaki Fumio's just an ordinary highschool girl in love......but then she finds out that the guy she's fallen for happens to like someone else.And then she gets into a fight with a friend... that and various other things are getting her really down......so she decides to go out and get a chainsaw.And take it to school.And kill the boy she likes, and herself afterwards.Along with anyone who happens to get in the way.