When Longmire reaches into the car to turn the engine off, he does not actually turn the key, he only flicks the keyring up and down.
When the young boy first stumbles upon the girl's body, her head is shown turned a little to her left and well backwards, with her eyes almost completely open. By the time that Walt first arrives at the crime scene, her head is turned further left and tilted a little forwards with her eyes almost entirely closed. We then repeatedly switch between these two different poses as the scenes progress.
During the shot in the opening sequence next to the female corpse, the dollar bill next to her head has the picture of Jefferson on it, not Washington.
At 13:28 -It is revealed that earlier, when Walt left his coat behind in the strip bar, he also left evidence in the pocket.