Captain Defenestrator

Chosen answer: Andy created the books so that everything was in the name of the Randall Stevens alias he created. The real books pointed to Warden Norton AND Randall Stevens, but didn't have Andy's name on them. As far as the law knows, Norton's accomplice was a guy named Randall Stevens who skipped town with the money before ratting him out.

Captain Defenestrator

If the laundered funds case was thoroughly investigated on an immediate basis (within a couple of days after the Bugle's writer got the material), the alias of Randall Stevens would have come out almost immediately, and of course his description would match that of someone who just escaped from prison, and even Barney Fife could have put two and two together.

Valid. However, by the time that would happen, Andy would be over the border and the warden would still get taken down, so his bigger goals would still be accomplished. They'll update Andy Dufresne's wanted poster to read "Alias Randall Stevens," but that's the biggest consequence for Andy.

Captain Defenestrator