The one woman (Jennifer Beals) is someone whom he met some time earlier and put into his mind she was a vampire and turned him into one. As to why he thought he was a vampire, guess the dude was insane? Not really sure, but it was an... experience... watching Nic Cage act. Kind of amazing I think, lol.

Edit: And yes, I realize this reply is 5 years later but assume someone will read it and maybe chime in on their thoughts.

I appreciate your reply. I don't think it is every too late to comment or reply regarding a film.

The couple - Rachel and her date - could have both been vampires or humans, or only Rachel was a real vampire who was dancing with her next victim. In any case, if Peter Loew wasn't already insane with delusions, Rachel sure pushed him over the edge.

@wonder2wonder said:

In any case, if Peter Loew wasn't already insane with delusions, Rachel sure pushed him over the edge.

Agreed, we see unstable folks all the time on the news walking our streets and sometimes - some final trigger sets them off "over the edge" and they commit some terrible crime.