If the dough was tagged with a transponder, they would have found it... and presumably eventually returned to the bank. Something might have gone wrong with the close quarters tracking. A modern car or truck is largely a Faraday cage, especially in the trunk.
This was apparently done in such a broad sweep, though, that the robber skated.
Actually, they caught him. They had to drop charges because the evidence was obtained in an illegal search. Ironic, is it not?