Volkswagen's "clean diesel" cars seemed like a dream come true for carbon-conscious drivers -- until a fraud of staggering proportions came to light.

Behind the lavish lifestyle of race car driver Scott Tucker lay a secretive lending empire built on tribal perks and profits from poor customers.

When drugmaker Valeant began to grow at dizzying speeds, investors were thrilled. But a handful of skeptics realized something was very wrong.

A trail of suspicious transactions led to startling revelations about banking giant HSBC and its ties to Mexico's deadliest drug cartels.

Donald Trump's image as a savvy businessman dazzled millions. But journalists and former associates describe an empire awash in drama and shady deals.