Many investigations are currently being performed remotely, in concert with the general counsel, the chief compliance officer, the chief audit executive, and depending on the how the allegation was triaged, with outside counsel, a forensic accounting firm, and the board. Even government prosecutors are interviewing witnesses remotely.
The primary goal of the interview is to elicit information in a non-coercive manner. My personal preference is always to conduct interviews face to face because I can control the subject and the