Per SCOTUSBlog,

The Court’s denial of review in U.S. v. Rayburn House Office Building Room 2113 (07-8160) left intact a ruling by the D.C. Circuit Court that gives members of the House and Senate some protection under the Constitution’s Speech or Debate Clause against criminal searches — even with a warrant — of their legislative offices. The specific search at issue involved the office of Rep. William Jefferson, Louisiana Democrat, who has since been charged with bribery and other federal crimes. The Justice Department appeal argued that the Circuit Court’s decision would seriously hamper probes of corruption and criminal conduct by lawmakers.  The congressman’s trial in federal court in Alexandria, VA, has been delayed while he pursues an appeal in the Fourth Circuit Court on a pre-trial issue.

The D.C. Circuit’s opinion is here.