The whole point of mules is for them to get burned. Assuming this was done properly, every single one of those 100 people can get caught and the cops won't be any closer to catching the people responsible.
That only holds true once the money has percolated up the chain - if they catch anyone in the window prior to the handoff, it could be of use.
Of course, if they pulled this off effectively, the drops all were probably executed soon after the 2h window, and then you've got a much colder trail to follow, even if you find one of the mules and magically have video surveillance of the region.
In all likelihood the handoff would be executed via bitcoins or a wire transfer by whoever is coordinating the operation in Japan. In all likelihood the people actually responsible for the hack are going to be eastern european or Russian, and once the money is no longer in cash it'll be gone forever.
