MIAMI - No one seemed to notice when a large white crane that had been working at the doomed Florida International University bridge lurched away down Tamiami Trail shortly after the span collapsed. There was a disaster to respond to: Mountains of concrete. Horribly mangled cars. Dead and injured people. It wasn't until some time later that authorities began wondering what happened to the crane and its operator, a close eyewitness who might help the investigation into the collapse. But he, and the crane, were gone. "He drove away in the crane and nobody stopped him,"