http://en.wikipedia.org/wiki/Nanterre_massacreRichard Durn is an interesting case
Durn had sent a letter to a friend in which he explained his plan: "Because I have by my own will become a kind of living-dead, I have decided to end it all by killing a small local elite which is the symbol of, and who are the leaders and decision makers in, a city that I have always detested." He explained that he intended to kill the mayor, "and then as many people as possible [...] I will become a serial killer, a mad killer. Why? Because I am frustrated and I do not want to die alone, because I have had a shitty life. I want to feel powerful and free just once."
