Why haven't any Wall Street tycoons been sent to the slammer?

More than a year into the gravest financial crisis since the Great Depression, millions of Americans have seen their home values and retirement savings plunge and their jobs evaporate. What they haven't seen are any Wall Street tycoons forced to swap their multi-million dollar jobs and custom-made suits for dishwashing and prison stripes. There are plenty of civil and class-action lawsuits from aggrieved investors angered by the losses in their mortgage bonds, hedge funds or pensions. Regulators have stepped up their vigilance after the fact. But to date, no captain of finance tied to the crisis has walked the plank.