Who is the purple man?

In many of the minigames there's a purple man who does very evil things. In the feed the kids minigame he is seen pulling up in a purple car, killing a child, then driving away. In another scene, he is seen telling Foxy to go out to the stage, but when Foxy gets there, there are 5 small skulls. There's another where Freddy Fazbear has to stop the Purple Man, but the game crashes and says "no you can't".

Who is he?

Nobody really knows, he is only mentioned as the "purple person".

This is the Purple Person's car:

This is the Purple Person himsellf:

(Images taken straight from the wiki)

The wiki states that:

As the player tries to serve cake to all six kids, a purple car will pull up outside and a purple person gets out, then proceeds to kill the sad child (who actually appears to stop crying and then cry even harder)

They refer to him several times only as the Purple Person, so his identity is actually unknown.

On the other hand, there are several theories for who the purple person is. One being he could be a security guard, or at least posing as one!

It is implied someone is tampering with the animatronics beforehand, which explains their aggression... although, theories suggest that it's the Marionette that's tampering with them due to pixelated post-death minigames pinpointing it as the murderer... Or do they? A mysterious purple man appears in some of the mini-games. In the cake mini-game, he seemingly kills someone, in another he's there when Foxy runs into a room of dead kids, and he can also appear in the Marionette chase◊ wearing a badge. The last one suggests the purple man was a security guard, or posing as one. This poses some odd questions. For example, if the purple man was the one who killed the kids, but the Marionette was the one who brought the dolls to life, is it possible that the Marionette was trying to save the kids in the only way it could?

Source

Source 2

Here's my theory (it's pretty long):

So I think the purple man is phone guy, and I have VERY strong evidence

1. In fnaf 2 phone guy says you take the day shift and he will take the night shift, he also says to stay VERY close to them.

2. the date is 1987 (during the bite of 87) so he tampers with freddy (freddy was the animatronic that bit jeramy (player) cause in one of the halls theres a poster that says:RULES OF SAFETY: 1. blah 2. don't run 3. don't cry 4. blahs 5. jibber jabber 6. DO NOT TOUCH FREDDY) so you are the the one who was bitten.

3. PG (phone guy) did this because jeramy knew to much. He thought that if your frontal lobe was bitten, you would die and no one would know.

4. lastly, in the minigame where you are following the marrionett (and secretly saying "S-A-V-E-T-H-E-M") you see the pm (purple man) with a phone in his hand and he has a badge (which resembles he was a person who worked there) and when he touches u it will glich up and in the bottom left corner it says "you can't"