In fnaf 4 you see the purple guy in the back room putting the head of springtrap on an employee. This suggests he was the creater of the spring lock suits or a high ranking employee. So when the kid was killed by Fredbear he was blamed. He was fired and left bitter. So he decided to take revenge on the resteraunt by shutting down by killing the kids.

BOOM!

4775721
Well... That doesn't really make sense. He is in SOME way related to the kid, so he would have gotten revenge over him. And even still, he also has a sort of relationship with the brother. He could be a father, or just a friend. Either way, he couldn't have gotten fired like that. He was either a technician, or a security guard.

4775748 IT....MAKES....SENSE.....TO.....ME.

4775721 There has to be something else because he wouldn't do that for being blamed, that would put him in deeper trouble. And I don't think the bullies were the souls because these are teenagers.

4775721 !