Updated

Rep. William Jefferson says the FBI crossed the line when it raided his congressional office and he wants a federal appeals court to order the return of documents.

Jefferson, D-La., says the raid last year was unconstitutional because it trampled on congressional independence. His lawyer argued that point Tuesday before a three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit.

His attorneys said nearly 19,000 pages of documents and electronic files seized by prosecutors and the FBI are covered by the constitutional principle that the executive branch may not use its law enforcement powers to infringe on the independence of the legislative branch.

Attorney Robert P. Trout told the court that the search was unconstitutional because, while FBI agents looked for documents related to their criminal investigation, they also examined many other records related to Jefferson's work as a legislator.

"How do we know an FBI agent — there were 15 FBI agents over 18 hours — didn't say, 'Hey Joe, get a load of this. This is really interesting,' " Trout said.

Trout said an attorney for the House should have been allowed to review the documents first to decide what should not be provided to the FBI.

The Justice Department countered that, if Jefferson had his way, targets of congressional bribery investigations could pick and choose what evidence to turn over to the FBI.

"In other words, the target of the search would be entitled to define the scope of the search," government attorneys said in court documents.

The raid was part of a 16-month international bribery investigation of Jefferson, who allegedly accepted $100,000 from a telecommunications businessman, $90,000 of which was later recovered in a freezer in the congressman's Louisiana home.

A federal judge authorized the unprecedented search last year, but the bulk of the investigation has essentially been on hold since last summer because of the legal fight.

Jefferson, who won re-election last year despite the looming investigation, did not attend the court hearing.

The case has cut across party lines and made for some strange alliances. Former House Speakers Newt Gingrich, a Republican, and Thomas Foley, a Democrat, have filed legal briefs opposing the FBI raid, along with former House Minority Leader Robert Michel, a Republican.

Liberal watchdog group Citizens for Responsibility and Ethics in Washington joined conservative groups Judicial Watch and the Washington Legal Foundation in supporting the legality of the raid.

The case is being considered by Chief Judge Douglas H. Ginsburg, Judge Karen Lecraft Henderson and Judge Judith W. Rogers.

All three served in the Justice Department. None served in the legislative branch, though Rogers was counsel to a congressional commission formed to review Washington's municipal structure. Ginsburg and Henderson were appointed by Republican presidents, Rogers by a Democrat.