The constable behind the counter at the Belgravia Police Station in central London raised his eyebrows in bemusement at the well-spoken middle-aged Englishman, wearing a suit and tie and overcoat, standing before him on a mid-October afternoon. The gentleman had short, receding black hair, close-set eyes, and a generous round chin. He mumbled darkly about Japanese organized crime—the Yakuza—and a corporate scandal he had uncovered in Tokyo. He claimed he had been the president and chief executive officer of a global corporation, had discovered that a fortune had gone missing, and then had been fired. He now had reason to believe, based on what he’d heard from journalists and fellow businessmen, that he might be killed.

The constable nodded, tried not to smile, and thought: This gent may be the biggest nutter we see all day. Most of those who showed up on the other side of the Plexiglas in the public room of the station and claimed to be targets of murder plots tended to be either deranged or exaggerating a petty money squabble. Still, the Metropolitan Police officers are trained to take seriously all such claims, and so the gentleman was shown into a private interview room, an 8-by-6-foot chamber with a desk and two chairs. He sat down across from the constable.

“Just Google my name,” the man insisted, “Michael Woodford. W-o-o-d-f-o-r-d.”

The constable excused himself and went to a computer where he typed in the name. What Google returned—approximately 6 million hits—was enough to prompt the officer to ask for ID. When Woodford produced it, the constable asked him to repeat his story to the duty officer, the ranking cop at the station.

Woodford, 51, recounted how he had just returned from Hong Kong, having fled Tokyo after a board meeting in which Olympus Chairman Tsuyoshi Kikukawa had fired him. The cause for dismissal, according to Woodford: his insistence that Olympus officials come clean about a series of questionable purchases dati...