Did Obama Advisor Resign Due to Federal Probe?

From ABC News:

When the White House announced last week it would be losing the services of Lewis A. Sachs, one of the president’s top economic advisers, the reason given for Sachs’s departure was that his work was largely complete. “He’s leaving now that markets have stabilized and Secretary [Timothy] Geithner has had time to set up a permanent team,” Treasury Department spokesman Andrew Williams said.

But Sachs’s quiet exit, reported in a blog entry on the New York Times web site, comes without any apparent next move for the Wall Street veteran, except for what he told the Times was his desire for time to “catch up on some sleep.”

Not factoring into the decision, Williams said, were recent reports suggesting Sachs’s old employer could be the subject of a federal probe. A December Times report said federal officials were then in the early stages of an investigation into companies that sold a complex breed of securities known as synthetic collateralized debt obligations, or C.D.O.’s, and then made financial bets against them.