When the telephone jingles at the headquarters of Marseille's police judiciaire, everybody scrambles to answer, for the caller may well be somebody with a thick French southern accent saying: "If you go to such and such a place, you will find a bundle of valuable stolen merchandise." A few years ago, the voice directed the cops to an $800,000 cache of jewels, stolen from the Aga Khan's wife, that had been returned, thoughtfully enough, to the front steps of police headquarters.
On February 14 of last year, an anonymous caller told the police to be on the lookout for a letter that...