Sergeant Pete Barnes (Dallas Police Department Crime Lab) lifted two partial prints from Tippit's patrol car. He testified that these prints were of no value. The prints were only partial and therefore would not contain enough points to match to any particular suspect.
Herb Lutz (a Michigan-based finger print expert) was shown a copy of these prints by Dale Myers and after studying them, determined that the two different prints were not those of Lee Oswald and that the prints most likely belonged to the same person.
Partial prints lifted from the patrol car that don't belong to Oswald does not in any way create reasonable doubt about Oswald's guilt. To do so, you'd have to show that the prints MUST belong to the killer.
Of these two partial prints lifted from the patrol car, one was lifted from the passenger front door and the other from the right front fender just above the tire. The prints most likely belong to the same person. Not even one eyewitness said the killer touched the right front fender just above the tire. If the killer never touched the passenger-side front fender just above the tire and the prints were left by the same person, then this would rule out the killer as the one responsible for leaving the prints lifted from the passenger door.