The trio first began talking to the retired real estate developer about buying some African diamonds because they wanted to get their families out of Sierra Lione, said lead investigator Michael Stempien, who cracked the case and was one of the officers who brought the men back from Upper Darby, Pennsylvania. [...] after a slight-of-hand “demonstration,” the three quickly enlisted the Stamford man’s help and money in trying to turn stacks of what appeared to be worthless black papers back into U.S.