When a congressman puts out a statement like this, you pretty much know it's not a good press day ...

Today, federal law enforcement officers executed search warrants on my Washington, D.C., and New Orleans homes as well as my vehicle in Washington. Subpoenas were issued to me, in my official capacity, to the clerk of the U.S. House of Representatives and to members of my Washington and New Orleans office staff. I do not know the extent or precise nature of this investigation but I am cooperating fully with the authorities.

That's from Rep. William Jefferson (D) of Louisiana.

Late Update: Here's an article with at least some information about this whole thing may be about.