When Special Agent Utah (Keanu Reeves) is checking up on Tyler's (Lori Petty) official police record on the computer, his partner (Gary Busey) reads aloud from the file that she's got black hair, but on the computer screen it states she's got blond hair.
Perhaps her natural color is blonde and that is what they have in the FBI file but at the time of the picture in the computer her hair was dyed black. Just a thought, not necessarily an answer.