In Eclipse, Bella originally thinks that it is Alice, since Alice has a habit of taking her clothing and replacing it with 'more stylish' choices. However, when Edward comes by he can tell from the scent that it was not Alice, but rather someone else. They believe that it was one of the newborn vampires in the area. Why they would want Bella's scent they aren't sure, but they are certain that Bella is now in dire trouble.