I don't know if it's THE official "Halloween" site, but it is AN official "Halloween" site. Of part 6, it says:
the Man in Black reveals himself to be a major character. He has been experimenting with pure evil all these years...and kept it all secret at the Smith's Grove sanitarium. Tommy and Dr. Loomis follow this madman to the sanitarium, where an all-out battle occurs with Michael.
yep his name is Dr Wynn, he actually also had a small role in the original Halloween. He was the head doc in charge of the asylum Michael escaped from, the guy Doc Loomis talked to the day after, for a quick 2 minute scene on the front steps of the place, before Loomis left and headed for Haddonfield.
He's the man who made Michael into the psycho serial killer we know and love, if you choose to believe that H4-6 actually took place, instead of ignoring them, like H7 and 8 do...