On the witness stand Jim Henderson says he saw Susan Connolly's car drive away. But he didn't see it, Perry did. Henderson was still inside the house as Susan's car drove away. In a conversation with Perry after the car drove away, he only deduced who would've been at his house at the time.
It's later shown he was lying to protect Susan.
Several of the witnesses have perjured themselves, yet neither Perry nor the presiding judge have mentioned this, or the charges they would be facing. The prosecution has totally failed its mission.
The blackmail photographer startles the unsuspecting couple exchanging money. Surprised, they both look directly at him as he takes the picture. But in the photograph, neither of them is looking directly at the camera. They're each looking slightly to the left - their right. The photograph is a frame grab of the scene as it was filmed, not the picture the photographer took.
In the opening court scene, it is clear that Perry's voice in dubbed in. It is a different volume and sounds different, than his voice later in the scene.
For several seconds around 17:40, as Perry and Mayor Henderson talk, you can see the marks on the floor where Henderson and a police detective eventually meet when the police arrive.