#and this poor guy randomly gets harassed sometimes bc he has very similar identification information to a suspected serial killer

[saving-people-haunting-things]

Okay so the idea that Sam's middle name is William comes from a screenshot of the investigation board in Toni's house in 11x23. However, that is a really bad source for many reasons:

One, Toni's stalker board is not a reliable source of information because she's really stupid. Two, it has not only the wrong mother's name (it's listed as Mary Catherine Howard instead of Mary Sandra Campbell), it also has the wrong birthday! (It says April 13th-- or maybe 18th or 19th it's really hard to read!) It also says that the father's middle name is Howard when John's middle name started with an E (it's also an odd repetition of the name Howard in my opinion). The father's age also seems a bit off (it's 2 or 3 years too old for the father to have been born in 1954).

The fact that it's from Lawrence, Kansas is correct, along with the father being self-employed (John co-owned a garage). But so many other things are wrong that it's very difficult to claim that this is Sam's actual birth certificate. It's either a fake, maybe John made it to enroll him in school with or something, or it belongs to some really unlucky random guy.

Either way, you can't definitively say that Sam's middle name is William, although it is still possible. William was one of the top 100 boys names for 1983, and it's a pretty common middle name even today. It's just not confirmed by that one background set decoration that was never intended to be looked at too closely.

What if I fought one of the Supernatural wikis?