The man who became Enron Corporation’s chief financial officer only a month after the energy giant declared bankruptcy has resigned.

The US Justice Department has opened a criminal investigation into Enron Corporation, whose employees lost billions when the company barred them from selling plummeting Enron shares from their retirement accounts.

US-based Enron Corporation, once the world’s largest energy trader, slid toward bankruptcy in one of the most spectacular downfalls Wall Street has ever seen after its would-be rescuer Dynegy Inc. backed out of an $8.4bn deal to take it over.