Kalifornia

If you're going to be trapped on a cross-country road trip with a serial killer, he may as well be Brad Pitt. David Duchovny plays a journalist working on a book about mass murder, when a serendipitous ride-share ad lands him and his photographer girlfriend in the same car with an honest-to-goodness killer and his troubled waif of a girlfriend (Juliette Lewis). That's what you call hands-on research.