The killer thought to be the 'purple guy' is not the true killer though because the purple shows shadow effects and who would have shadows in the day? Well no-one would. Wait how is it that a person is in the restaurant after hours i hear you ask. The only person who could be the 'purple guy' is the night guard. Stuck in the shadows of the hellish job.
In FNAF 3 people believed that the death of the purple guy is the death of the killer but no. the killer would be about 50-70 years old and cannot run as fast as the cut scene. The cut scene shows the 'purple guy' running as fast as foxy can meaning he is not the killer. He is the innocent night guard of the FNAF 2 security guard. The spring trap is the guard!
Hope you enjoyed this theory.
Check out these YouTube accounts:
GameTheory
GTlive
8-Bit gaming
8-Bit Ryan
Other Ryan
Smike
and why not,
PopularMMO's