Song Mystery

There is a piece of choral music I've heard numerous times in horror/drama movies, movie trailers and even in TV programs over the years... always in the background.. never, to my knowledge, as a cut on a soundtrack. Following is a summary of what I've learned about it from various forums. You can hear samples here:

Krays Movie Trailer with voiceover

Friday in Hell .swf (music only no chorus) heard in beginning

Apparently it was also heard in 'Curse of the Exorcist' on the E True Hollywood story. They played it about an hour and 10 minutes into the 2 hour show. It was right when they were coming back from commercial and into another segment.

It has been incorrected identified as "The Toccata and Fugue in D Minor" or "O Fortuna", but it isn't either of those. I'm more a 50's-70s rock and roll music kinda person. I have no knowledge about classical-sounding music, so when I heard a piece I like, I never know what it is! I've seen a lot of forums where people are trying to figure out what this is, but so far, no answer. Hopefully someone here has the resources to figure it out.

I'd love to get an answer so I get this hauntingly scarey choral music.

Thanks so much to anyone who can figure this out.

CG