If you consider that it should compensate you for the money it took off you, then Colorado has a law on the books governing the compensation process, which Thomas (and the previous court - the Colorado Supreme Court) thinks you should follow.
The majority opinion seems to be that not quickly returning (and it considered it as returning rather than compensating) the innocent parties property offends their right to due process.
Which in the general case is pretty clearly true. If someone is arrested and found not guilty, have their conviction overturned on appeal, etc. they're not in general entitled to payment for lost wages, legal costs, etc. It seems reasonable to consider this a different situation in that it involved a specific fine but I can at least see the counterargument that it's not.