Inside Story of Missing Billionaire Whose Luck Ran Out on Superyacht

Less than half of one percent of federal criminal cases end in an acquital, so billionaire Mike Lynch and his co-defendant, Stephen Chamberlain, seemed to be the luckiest of unlucky men on June 6 this year, when they were found not guilty on fraud charges that could have landed them in prison for 25 years.

But a month after that ebullient moment on the 17th floor of the federal courthouse in San Francisco, their fortunes took a tragic turn.

On Saturday, Chamberlain...