Answer:
The answer to the question: What should the investigator do when learning of the crash, would be: To report the adverse events of the broken wrist and the mild concussion.
Explanation:
This is the protocol when investigating about a crash. First comes the investigation of the adverse events, caused to the person, or persons, involved in the crash, as whatever comes from these events will have to be taken care of first. Then, after that, any other issues may be investigated. These adverse events are born from the broken wrist and the mild concussion.