If I'm not mistaken, the jacket was found before Saint Oz was arrested.
The conspirators were amazingly fast in planting that jacket replete with fibers in it that match the shirt Saint Oz was wearing, weren't they ?
It's positively amazing that the conspirators knew that Saint Oz would be arrested without a jacket and that his landlady would report that he was wearing one when he left the boarding house.
Poor Saint Oz. More evidence that points to the innocent patsy's guilt.
He really had a bad day.