Walter Mashburn is a playboy billionaire who has assisted the CBI on two cases. In one he was initially a suspect, but went on to help catch the real killer. In another he was the target of a assassination by a rival billionaire, ans was nearly balmed for the man's death, until it was reveal that the man had faked his own death in a plot to bring down Mashburn.Mashburn had a brief fling with Lisbon.