I think purple guy was framed. I think the guys in the suits may have killed the kids. If you guys remember, someone used a "golden suit" to lure the kids to the back. How could purple guy have killed the kids if he was inside the office at that time? It was not purple guy who killed them. It was either the guy in the springtrap suit or the guy in fredbear's suit. They must have framed him. The only reason why purple guy was inside the horror attraction was because of the fact that he was trying to figure out who killed the kids. He noticed that the ghosts of the children were there when he was near the "springtrap" suit. Purple guy got scared when he saw the ghosts of the children. If one of those where his kid(s) it would be the one who was making purple guy back away as he got closer. Purple guy must have thought his kid, or the others would go into a different place (heaven) instead of staying where they died. The kids found him in the room and tried to apologize to him because they knew who killed them.
that is all I got, for now...
Nice Theory,Gurl
I think it was vice versa and purple guy framed one of the guys in suits. Because the newspaper on the wall in FNAF 1 said the man arrested by the police was convicted. If it was purple guy, he wouldn't be released from prison so soon.