Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

This is another Dallas motorcycle cop from the day of the assassination- I don't know which one.

So again, we see the straight arm going out diagonally to the handgrip of the motorcycle. And here is Mary Moorman's own picture of Glenn McBride:

Again, the straight arm. So, how did they come up with this?

That is not a straight line. That is a wierd, impossible, non-anatomical jointed line. And it may be one of the reasons they had to install the thumbprint over it.

And by the way, pressing one's clean thumb into a dry photograph does not leave a mark. The guy who did that must have had his thumb coated with something.