A prominent Washington businessman who is caught up in a campaign finance investigation is fighting to restrict the government’s ability to review tens of millions of pages of documents seized from his home and office.

Federal agents in March executed search warrants against Jeffrey Thompson, a longtime accountant and founding member of a professional services firm who is enmeshed in a probe over the 2010 mayoral election of Vincent Gray. Lawyers for Thompson, who has not been charged with a crime, want the U.S. Court of Appeals for the D.C. Circuit to limit the scope of the documents that investigators can review in the high-profile corruption probe.

At issue in the dispute is the use of a government “filter” or “taint” team to inspect 60 boxes of documents and 23 million pages of electronic files. Filter teams serve as an ethical barrier designed to keep privileged information out of the hands of the prosecution team.

Federal judges have long struggled over how much flexibility to give prosecutors to review documents without violating a person’s attorney-client privilege. Across the country, there’s no clear standard. Some judges have declined to allow government filter teams to review information that is potentially privileged.

Thompson’s attorneys, including Williams & Connolly partner Brendan Sullivan Jr., contend the proposed filter team is invalid because it is made up of government lawyers. The lawyers want to do their own search for privileged information without help from federal investigators.

Chief Judge Royce Lamberth of U.S. District Court for the District of Columbia last month ruled in favor of the U.S. Attorney’s Office for the District of Columbia, saying in an opinion that “the court has no reason to doubt the good faith of the government or its willingness to abide by the procedures it has suggested.”

Lamberth unsealed the ruling on May 25. The 14-page redacted opinion doesn’t name Thompson, but the Web address for the ruling identifies the document as “Thompson Order.” Two people familiar with the Gray campaign finance investigation confirmed that Thompson is fighting the government over the attorney-client privilege in the U.S. district court. Sullivan and a spokesman for the U.S. attorney’s office, William Miller, declined to comment.

Thompson’s lawyers have asked the appeals court to put the government’s document review on hold pending the challenge. Prosecutors on May 30 said they are opposed to a stay.

ONGOING INVESTIGATION

Prosecutors in Washington have not kept secret the ongoing investigation of the Gray mayoral election campaign, a probe that has landed on the front page of The Washington Post. Published reports in recent months characterized Thompson, a founder of Thompson, Cobb, Bazilio & Associates, as one of the city’s largest political donors.

Last month, two of Gray’s campaign aides, Thomas Gore and Howard Brooks, pleaded guilty to their roles in a scheme to divert funds from Gray’s campaign to the campaign of a challenger.

U.S. Attorney Ronald Machen Jr. said in a statement on May 24 that “underhanded” activity with campaign funds “tainted the integrity” of the mayoral campaign. Machen praised Brooks for owning up to mistakes and telling the truth. “We urge others to do the same as we continue our efforts to get to the bottom of what happened during the 2010 election,” he said.

The ongoing dispute over the Thompson documents could delay how swiftly prosecutors wrap up the Gray campaign investigation. Prosecutors told Lamberth that the government has not yet inspected the millions of pages taken from Thompson. The government, Lamberth said, proposed using a filter team to review the documents at the same time that Thompson’s team would conduct their assessment of the files. The sides would then submit any privilege disputes to a judge for resolution.

Thompson, however, objected to the procedure, arguing that his team alone can conduct a substantive privilege review without government intrusion. Thompson’s legal team pointed to a D.C. Circuit decision in 2007 over the propriety of search warrants concerning then-Rep. William Jefferson (D-La.), the target of a public corruption probe.

At issue in the Jefferson dispute was whether the seizure of documents from a congressional office violated the Constitution’s speech or debate clause, which gives some protection to legislative files and testimony. The D.C. Circuit said a judge must first conduct the privilege review and return any protected documents to the congressman.

Gregory Poe, a name partner at Washington’s Poe & Burton, said in a friend-of-the-court brief in support of Jefferson that “filter teams are nothing more than blunt objects masquerading as surgical instruments.”

The Thompson dispute gave Lamberth the chance to test the boundaries of the Jefferson decision. The judge said he was “loathe to apply” the Jefferson ruling “beyond the exceptional circumstances posed in that case.” Under the government’s proposed review process, Thompson has a chance to assert privilege claims before the investigative team ever sees the information. That wasn’t the case in the Jefferson matter, Lamberth said. Lamberth said he is confident the procedures in the Thompson document review will ensure the investigation team does not have access to potentially privileged documents.

“Indeed, the government has every incentive to abide by its procedures, because any leaks between the filter team and the investigation team…may lead to a violation of the petitioners’ Sixth Amendment rights and will compromise the prosecution’s ability to secure a conviction,” the judge wrote.

NO SINGLE STANDARD

The U.S. Justice Department’s manual on the search and seizure of computers, last updated in 2009, said the “preferred practices for determining who will comb through the files vary widely among different courts.”

Prosecutors prefer to use filter teams over special masters, who “often take several years to complete their review.”

No single standard has emerged through court rulings in recent years, according to the manual’s authors, including the Justice Department’s Nathan Judish, a senior counsel in the computer crimes and intellectual property section.

The Sixth Circuit in 2006, for example, “expressed discomfort” with filter teams in connection with grand jury subpoenas, but not in relation to search warrants.

In 2007, U.S. District Judge Richard Roberts in Washington ordered a special master to review electronic information for any privileged communication. The use of a special master, Roberts said, “will best promote the appearance of fairness.”

Lamberth said in the Thompson dispute that he is unaware of any circumstance that would “give rise to any special appearance of impropriety through the use of a filter team.” Still, the judge said the use of a filter team viewing privileged documents “will have some chilling effect, if only marginal,” on communication between lawyers and clients.

Mayer Brown white-collar defense partner Kelly Kramer, who is not involved in the Thompson dispute, said courts have recognized that taint teams “pose real risks to privilege holders” and that they should only be used when there is no viable alternative.

“What is curious here is that it seems there is a perfectly good alternative: letting the defense conduct the privilege review,” said Kramer, who has litigated privilege issues flowing from search warrants. “In fact, the opinion seems to suggest that the defense and the taint team may be reviewing the same documents at the same time. If that is right, it is hard to see what good purpose is served by the taint team.”

Mike Scarcella can be contacted at mscarcella@alm.com.