Near the end, a vampire serial killer explains that he lived in a hippie commune in California in the 60's and that drugs, free love and Joni Mitchell music made him what he is! He adds that a lot of the communes at that time had vampires in them.
Colin transcribed the Joni content in the following dialogue:
William shrugged.'Oh, we've always been here. This used to be a commune - California-dreaming hippies, mind-altering drugs, Joni Mitchell music. Our parents were hippies. We were isolated from other ways to live and think, so we depended on each other. My brother and I are unbelievably close. But we're nothing really. We're here to serve the Sire.'
And Janine adds that this book is part of Patterson's Alex Cross series.
(Contributed by Milsac, Colin, Janine)