“Attorney–client privilege is dead!” President Donald Trump tweeted early April 10.

The pronouncement came on the heels of reports that the FBI executed search warrants at the Manhattan office of Trump’s personal attorney, Michael Cohen, April 9. They also reportedly searched his Manhattan hotel room.

“Today the U.S. Attorney’s Office for the Southern District of New York executed a series of search warrants and seized the privileged communications between my client, Michael Cohen, and his clients,” Cohen’s attorney Stephen M. Ryan of McDermott Will & Emery, Washington, said in an April 9 statement. The Southern District of New York covers Manhattan, the Bronx, and some areas outside the city.

Ryan said the search warrants were “completely inappropriate and unnecessary,” and that they “resulted in the unnecessary seizure of protected attorney client communications between a lawyer and his clients.”

Despite Trump’s and Ryan’s protests, special search warrant procedures exist to protect the attorney-client privilege, according to former federal prosecutors who spoke to Bloomberg Law.

There’s also the possibility that at least some of the evidence gathered from Cohen isn’t protected by the privilege at all.

Cohen surfaced recently as a figure in the “Stormy Daniels” affair. He paid $130,000 to the adult film star, whose real name is Stephanie Clifford, to prevent her in the run-up to the 2016 presidential election from speaking about her alleged tryst with the president.

Though it’s unknown—for now—exactly what the FBI was looking for or what it took from Cohen, the Washington Post reported that Cohen is under investigation for possible bank fraud, wire fraud, and campaign finance violations.

Ryan also said in the statement that he had “been advised by federal prosecutors that the New York action is, in part, a referral by the Office of Special Counsel, Robert Mueller.”

‘Special Policies’

“Attorneys often have documents that are relevant to criminal investigations and so they are subject to searches like any other person,” Harry Sandick told Bloomberg Law.

Sandick was previously a prosecutor in the Southern District of New York, the office that, according to Cohen’s lawyer, oversaw the Cohen search warrants. He’s now a partner at Patterson Belknap Webb & Tyler LLP, New York.

But “there are special concerns when searching the offices or homes of lawyers,” Sandick said. “As a result, DOJ has special policies that require additional levels of approval and special protocols to prevent attorney-client privilege from being compromised,” he said.

“There’s a very basic reason for” these protections, former New York federal and state prosecutor Daniel R. Alonso told Bloomberg Law: “These kinds of enforcement procedures can have an effect on legitimate attorney-client relationships.”

These added protections mean getting more approvals within DOJ than would otherwise be required.

Getting search warrants for a lawyer’s office “cannot be done by a line prosecutor with a unit chief’s approval,” Sandick said.

“And if there is another way that the documents can be obtained, the prosecutor should pursue those avenues first, before searching a lawyer’s office,” he said.

Plus there are “clean teams"—prosecutors who are not involved in the underlying case—"who review the materials to make sure that privileged documents are not used in the prosecution,” Sandick said.

“DOJ goes through specific steps using a walled-off group of prosecutors to conduct an initial review so that the prosecutors handling the case are not ‘infected’ by seeing attorney-client privileged materials,” he said.

Subject, Target, Witness

Different procedures apply depending on whether the attorney is a subject or target of the investigation, or a disinterested third-party, Alonso said. He is now managing director and general counsel at Exiger, a global governance, risk, and compliance firm.

If the attorney is a subject or target, “the U.S. Attorney has to personally approve” the warrant, he said. They also have to consult with the Office of Enforcement Operations of the Criminal Division in Washington, although its approval wouldn’t be required, he said.

The interim U.S. Attorney for the Southern District of New York is Geoffrey S. Berman, who was appointed by Attorney General Jeff Sessions and is reportedly recused from the investigation.

The approval could have been delegated to another assistant U.S. attorney working under Berman, Alonso said.

“Sometimes the U.S. attorney is out of town or not available, and so there’s a whole chain of delegation of acting U.S. attorneys,” he said.

When authorities don’t consider an attorney to be the subject or target of an investigation, “it’s a little bit harder” to get approval, Alonso said.

“If the lawyer is merely a disinterested third party, then you need approval from both the U.S. Attorney and a deputy assistant attorney general in Washington,” he said. It should generally be handled by a subpoena or a voluntary request for evidence rather than a search warrant, he said.

Not Only Trump’s Lawyer

These special procedures aren’t only in place for presidents’ lawyers, Sandick pointed out.

New York lawyers, in particular, might remember the prosecution of lawyer Lynne Stewart, who was convicted in 2005 of aiding terrorism by smuggling information from an imprisoned client to his followers in Egypt.

“S.D.N.Y. prosecutors conducted a search warrant at her office,” Sandick recalled.

“The prosecutors who reviewed those materials in the first instance were not prosecutors who worked on any case involving Stewart or her clients,” he said.

Narrow Privilege

“Not everything that a lawyer does is within the scope of the attorney-client privilege,” Sandick noted. “This is a narrow privilege meant to protect only the rendering of legal advice,” he said.

Giving business advice and communicating with people other than the client, for example, aren’t covered by the privilege, he said.

“Finally, if a person uses a lawyer to commit a crime, the attorney-client privilege is waived pursuant to what is called the crime-fraud exception,” Sandick said. “This is not a commonly invoked exception, but sometimes lawyers do assist their clients in committing crimes,” he said.

Former Southern District of New York U.S. Attorney Preet Bharara, whom Trump fired, reminded Trump of this: “Long live the crime-fraud exception,” he tweeted.

Mueller Effect?

It’s “guesswork and inference” how these warrants relate to Mueller’s investigation, Sandick said.

The U.S. Attorney’s Office involvement may be a courtesy because the search is in their district, he said..

“Another possibility is that S.D.N.Y. will itself be the ‘clean team’ here,” he said.

Or it may be that this investigation simply falls outside the scope of Mueller’s, he said.

Even if so, the resulting evidence could still work its way back to the special counsel, Alonso said.