In my campaign I'm running, all of my characters are good. But there's one character who's evil. And everything he does is making it harder for me, as a GM and for the players. He kills important people, he burns down buildings, etc. He's done this twice before, in one campaign he killed the other players. Pissing everyone off and cutting the campaign short. In another one he did nothing but setback the players on their journey. And he's doing it again. I want everyone in my games to have fun but nobody is when he's playing like this. I want my players to kill him, but they aren't too good at RPing so the Lawful Good Paladin looks past his murders and such. I don't want to have to kill him and remove him from the game but it seems like the only option. What can I do to try and stop this without going to extremes as to remove him from my game?