The below clip of Jessica Alba is taken from a promo clip of the film The Killer Inside Me that can be found at http://wildbunch.info/. In the clip, Alba's character is shown lying on her stomach on a bed getting her bare butt whipped. The question is whether the butt in question is Jessica's or a body double. While you see some face in the scene, it is blurry and hard to tell if it is her. Personally I am leaning toward a body double, but there are apparently people who disagree so here is the clip so you can judge for yourself.

http://www.fileoo.com/index.php?file=ca_Alba_the_killer_inside_me.avi
http://rapidshare.com/files/302458616/jaalki.rar