[newbusox]

I would guess that the office to contact would be the US Attorney's Office for Washington, D.C., http://www.justice.gov/usao/dc/about/contact.html. They (and possibly others US Attorney's Offices) almost certainly have jurisdiction.

For those interested, the anti-bribery statutes are at 18 U.S.C. 201 (http://codes.lp.findlaw.com/uscode/18/I/11/201) and subsequent provisions within that chapter (there are also other, conceivably applicable statutes that might be charged in bribery or corruption cases). As you can see, the wording in the statutes is extremely broad so, if so inclined, it's possible to make an argument that many, many things are bribery (although, realistically, "bribery" has been significantly narrowed by the courts).