President Donald Trump is infuriated after investigators on Monday raided the office and a hotel room of Michael Cohen, his personal lawyer and longtime confidant.

Cohen is a central figure in several investigative threads relating to Trump and privy to the president's finances and business dealings.

"This just got personal for Trump," a former federal prosecutor said. "It hits close to home, and he's scared."

Experts said Trump's anger was most likely also fueled by the knowledge that even if he moves to stonewall the investigation into Cohen, investigators have other avenues through which they can publicize their findings.

President Donald Trump is enraged, but there may not be much he can do about it.

The latest trigger: raids by the FBI on Monday morning targeting Michael Cohen, his personal lawyer and longtime confidant.

Armed with a search warrant, the FBI raided Cohen's Manhattan office and his hotel room after a referral from the special counsel Robert Mueller, The New York Times reported.

Investigators working with the US attorney's office for the Southern District of New York are said to have gathered documents on various topics — such as a $130,000 payment to the porn star Stormy Daniels shortly before the 2016 election — as well as a computer, a phone, personal financial records, and attorney-client communications.

Trump went back to a frequent line of attack Monday evening, calling the raids a "witch hunt" and "an attack on our country."

Later, The Times reported, Trump privately fumed to his aides and began floating the possibility of firing Rod Rosenstein, the deputy attorney general who oversees the Russia investigation and the Southern District.

Trump is said to have been angry enough that his advisers worried whether he would use the raids as a reason to fire or order the firing of top Justice Department officials in charge of the Russia investigation.

"This just got personal for Trump. It hits close to home, and he's scared."

"This just got personal for Trump," said Jeffrey Cramer, a former federal prosecutor who spent 12 years at the Department of Justice. "It hits close to home, and he's scared."

Cohen, whose primary and highest-profile client is the president, left the Trump Organization early last year and has been a personal attorney to Trump since then. But his relationship with Trump spans years — he has long been known as one of Trump's closest allies.

Cohen's knowledge of Trump's finances is most likely an aggravating factor for Trump, who warned last year that investigators would cross a "red line" if they ventured into his or his family's financial dealings.

"This search warrant is like dropping a bomb on Trump's front porch," Joyce White Vance, a former federal prosecutor from Alabama, told The Washington Post.

"You can't get much worse than this, other than arresting someone's wife or putting pressure on a family member," Mark Zaid, a Washington attorney, told The Post. "This strikes at the inner sanctum: your lawyer, your CPA, your barber, your therapist, your bartender. All the people who would know the worst about you."

Trump goes off

Michael Cohen's relationship with Trump dates back to when he bought an apartment in Trump Tower in 2001. Jonathan Ernst/Reuters

Cohen is a central figure in at least four investigative threads related to Trump and his finances.

The Post reported that investigators were looking into whether Cohen, who's also a subject of scrutiny in the Russia investigation, committed bank fraud or violated campaign finance laws.

If the records investigators seized were related in any way "to hush money bank fraud or campaign finance violations, then the president faces significant legal exposure," said Andrew Wright, an associate in the White House counsel's office under President Barack Obama.

Trump could also face heightened liability if Cohen is forced to testify against his clients or flips and becomes a cooperating witness for the FBI.

Trump made clear he was still heated about the episode on Tuesday morning.

"Attorney-client privilege is dead!" the president tweeted a little after 7 a.m. ET. "A TOTAL WITCH HUNT!!!"

Prosecutors must meet a high legal standard to justify a search warrant for a lawyer, as attorney-client privilege is a lauded aspect of the justice system.

Much of Trump's fury since Monday has been directed at Mueller, though the raids were not carried out by investigators working for the special counsel.

The interim US attorney for the Southern District of New York is Geoffrey Berman, a Trump appointee with ties to Rudy Giuliani, the former New York mayor who's a close ally of the president's. Berman also donated to Trump's 2016 campaign.

"Trump can't go after a guy he appointed, so he targets Mueller, because that's what riles his base up," Cramer said.

But that might change.

ABC News reported Tuesday that Berman had recused himself from the district's investigation into Cohen and had no role in approving the raid. The report is likely to infuriate Trump, who often rails against Attorney General Jeff Sessions for recusing himself from the Russia investigation and is said to have considered replacing him on multiple occasions.

But in this case, experts say that even if Trump were to remove or replace Berman, it would not hinder the investigation into Cohen.

'The president can't stop this train'

Trump could pardon Cohen for federal crimes — but not for state ones. Alex Wong/Getty Images

The Southern District of New York — often dubbed the Sovereign District of New York — is one of the most highly regarded US attorneys' offices and has long had a reputation for remaining apolitical.

"Firing the US attorney at the SDNY wouldn't hurt or shut down the investigation at all," Cramer said. "The president can't stop this train, and it's careening off the tracks. He can pardon people, but he cannot stop the train."

The extent of the office's role in the Cohen raids is difficult to gauge without more details about the search warrant.

According to The Times, the office carried out the raids after receiving a referral from Mueller's office, most likely after it uncovered evidence of wrongdoing related to Cohen that was not within the special counsel's investigative focus.

Cramer said a referral of this nature was not unusual, adding that in the event that prosecutors discover information relevant to Mueller's investigation, they are likely to cooperate with the special counsel's office.

But Southern District veterans raised two other possibilities about the office's role in the matter.

"I need to see more specific reporting before I'm 100% convinced this is a full-on 'referral' to SDNY," said Preet Bharara, the former head of the office whom Trump fired last year. "I could be completely wrong but such a referral seems peculiar. Of course much is peculiar these days."

Harry Sandick, a former assistant US attorney at the office, also said he had a lot of "unanswered questions" about its involvement in the raids.

"One possibility is that because the premises that needed to be searched were within the district, the office would play a part in getting that search warrant," Sandick said. "That's not uncommon, because in general, when you want to search a place within the district, you need a warrant from them."

Another possibility both Bharara and Sandick suggested was that the office was acting as a "taint team" for Mueller.

One way or another, the truth is going to get out.

A taint team is an internal group, walled off from investigators, that the government sets up when it seizes electronically stored documents with a search warrant.

The team's primary responsibility is to separate materials that are protected by attorney-client privilege to avoid later claims that the government improperly accessed the documents, according to the New York Law Journal.

"The SDNY might do this, because that entire office can be kept separate from Mueller's office to the extent that there are privileged materials that need to be reviewed," Sandick said. "That way, Mueller's team can't be accused of improperly using information obtained from the warrant."

In that scenario, the office would be responsible for collecting all evidence, sorting out non-privileged materials, and handing it to Mueller, said Matt Miller, a former Justice Department spokesman. In other words, the case would not have been a full referral and could still be within Mueller's scope.

Cramer said Tuesday that Trump's anger was not surprising given the enormous implications of the Cohen raids.

While he may not be able to shut down the investigation into Cohen, Trump could theoretically pardon anyone convicted of a federal crime.

But even if he were to do that, Cramer said, "the New York attorney general is going to pick up this trail, and that's where the president has absolutely no authority, because he can't pardon state crimes."

"One way or another, the truth is going to get out," he added. "It may be in an indictment; it may be in a report. But sooner or later, everyone will know what Bob Mueller knows."