I’m not a CTer, but I would defend Oswald by having him testify that he found and rifle on the sixth floor and picked it up. He wished he didn’t do that. Then, 45 minutes later, while out for a walk, he saw a police officer had been shot, found a gun laying on the ground and picked it up. He wished he didn’t do that. He intended to turn the gun over to the police so he put it in his pocket but then forgot about it.