More revelations about this photo. They are all moving the same direction, towards us. They are heading into the Homicide Bureau, presumably for an interrogation. In the rear is Fritz himself. You can tell it's him because of his thick horn-rimmed glasses. In front of him is Bookhout, and in front of him the two detectives with Oswald. They are all moving the same direction. And then you have that errant hat which is moving the opposite way. But, under the circumstances, how could he? There is no space for him to get around Fritz and Bookhout. He's trapped.
I'm telling you: that is nobody. It's just a hat, perched in space. And it was put there to cover up the face of James Bookhout. This is most definitely a smoking gun.