Not a lot of detail yet:

FBI and Internal Revenue Service agents searched the home of U.S. Sen. Ted Stevens on Monday.

Investigative sources told FOX News that the FBI executed a search warrant at the Girdwood, Alaska, house. Sources would not detail what the search team is looking for, but said agents continued to do extensive work at the property late Monday.

Stevens, who was formerly chairman of the Senate Appropriations Committee, has reportedly been under investigation for exchanging federal contracts for bribes, illegal gratuities and unreported gifts from VECO Corp., Alaska’s largest oil-field engineering firm.

Update (AP): Sounds like they think VECO might have bought him a house, or at least part of one:

In May, the Anchorage Daily News revealed the FBI was investigating whether the firm had paid for expansion work to Stevens’ home in Girdwood, performed in 2000. Stevens has said he paid invoices for the work from his own pocket.