"It was like a party," one former loan underwriter tells "Frontline's" Martin Smith. "We were getting through these loans as quick as we can. They were not being looked at like they should've been looked at."
'Frontline' Learns Firsthand Why Wall Street Is 'Untouchable'
Why haven't any senior Wall Street executives gone to jail for the financial crisis?
Since the financial system's collapse four years ago, that question has been asked over and over again. The question has sparked editorials, Congressional commissions, Oscar-winning documentaries and the Occupy Wall Street protests