They arrived before dawn, forced the front door lock and burst in with a no-knock warrant, tactics typically used in a major drug bust. The agents seized Manafort’s tax, banking and real estate records, photographed his expensive antiques and tailored suits, and hauled away a trove of material.

Manafort, once a high-flying Washington lobbyist, now is awaiting trial on a dozen federal charges, including fraud, conspiracy and money laundering of more than $18 million in an elaborate scheme that prosecutors allege extended through the period he led Trump’s campaign. He has pleaded not guilty.

The dramatic case is being helmed, in part, by Andrew Weissmann, a senior deputy to special counsel Robert S. Mueller III, in the wide-ranging investigation into Russian meddling in the 2016 election and whether Trump or his aides committed crimes before, during or since the campaign.

At 59, Weissmann casts a broad shadow in the Mueller probe, a veteran federal prosecutor who has built a reputation for aggressive tactics and a no-nonsense demeanor. Both his supporters and his detractors agree he is hard-charging and to be feared.

“He’s tenacious, and very smart,’’ said Bradley D. Simon, a defense lawyer who worked alongside Weissmann as an assistant U.S. attorney in Brooklyn in the 1990s. “He really got enormous results. He won a lot of big, high-profile cases.”

Weissmann’s approach — and his expertise in uncovering perjury, obstruction of justice and complex financial crimes — now could pose a mortal threat to Trump’s presidency.

Trump’s lawyers have sparred with Mueller since last year over whether, and under what conditions, the president would submit to an interview. Weissmann is a likely choice to take the lead in any direct questioning of the president.

That has made Weissmann a prime target of Trump’s allies and surrogates, especially on cable TV. Sean Hannity, whose weeknight Fox News show pummels Trump’s presumed foes, has said Weissmann “not only needs to be fired but fully investigated.”

Hannity vilified the prosecutor during 14 episodes in December and January alone, according to transcripts of the show, cable’s most watched news program. Other conservative commentators, notably radio’s Rush Limbaugh and Fox News’ Lou Dobbs and Laura Ingraham, have joined the attack.

The critics often cite Weissmann’s political contributions. Federal Election Commission records show he donated a total of $6,650 to the presidential campaigns of Hillary Clinton and Barack Obama and to the Democratic National Committee from 2006 to 2008.

Weissmann was out of the government at the time, employed by Jenner & Block, a law firm that specializes in corporate litigation.

The contributions by Weissmann and eight other lawyers on Mueller’s team led critics to accuse the group of partisan bias. But federal regulations bar the Justice Department or a special counsel from considering political donations as a basis for employment.

Weissmann’s critics also cite the supportive email he sent Sally Yates, then the acting U.S. attorney general, on Jan. 30, 2017. Trump had just fired Yates for refusing to enforce his order to ban residents from seven Middle East countries from entering the United States.

Whatever his politics, Weissmann has worked closely in the past with Mueller, a registered Republican who headed the FBI from 2001 to 2013. Weissmann was Mueller’s legal advisor for national security in 2005 and later served as FBI general counsel for two years.

Weissmann was leading the Justice Department’s criminal fraud section when Mueller recruited him in early June for the special counsel probe. So far, they have overseen indictments of four former Trump aides, plus others.

Manafort and Richard Gates III, Trump’s former deputy campaign chairman, face similar charges relating to their lobbying work for the government in Ukraine. The Times reported Sunday that Gates, who asserted his innocence in October, will plead guilty in coming days. Michael Flynn, Trump’s former national security advisor, and George Papadopoulos, a former campaign foreign policy advisor, pleaded guilty to lying to the FBI and are cooperating with Mueller’s team.

An additional indictment was made public Friday – charging 13 Russian nationals and three Russian entities with interfering in the 2016 presidential election by exploiting counterfeit identities of individuals and entities. Those charges are in part related to a separate guilty plea, also unveiled Friday, of a computer specialist from Santa Paula, Richard Pinedo, who admitted to selling fake identifications. Pinedo was unaware his customers included the Russian operatives, according to the documents.

A spokesman for Mueller, Peter Carr, declined to comment on Weissmann’s career and said that Weissmann would not comment for this article.

A graduate of Princeton and Columbia Law School, Weissmann first made his mark as a federal prosecutor in New York City in the 1990s, leveraging evidence and threats of lengthy prison sentences to “flip’’ mob underlings to testify in trials of organized crime bosses.

In 1997, Weissmann led the team that convicted Vincent Gigante, who headed the powerful Genovese crime family. Gigante had avoided trial for years by feigning mental illness, at times wandering the streets of Lower Manhattan in his bathrobe and slippers, mumbling to himself. New York tabloids dubbed him “The Oddfather.”

But Weissmann’s biggest catch was a white-collar case that helped define the go-go years of easy money and lax enforcement: Enron.

After the giant Houston-based energy conglomerate collapsed in 2001, Weissmann helped lead what the FBI called the “most complex white-collar crime investigation’’ in its history.

He oversaw prosecutions of more than 30 people on charges that included fraud, perjury and obstruction. Three of Enron’s top executives were among those convicted.

“If there’s something wrong, Andrew Weissmann is the type of person who won’t freakin’ give up,’’ said Mary Flood, a lawyer who tracked the Enron cases as a reporter for the Houston Chronicle.

Weissmann also successfully argued in U.S. District Court that Enron’s major outside auditor, Arthur Andersen, had covered up the losses at Enron and had shredded documents to hide its role. The long respected Chicago-based firm was convicted of obstructing justice and effectively went out of business in 2002.

But Weissmann soon came under fire for having pushed the legal boundaries.

In May 2005, the U.S. Supreme Court unanimously overturned the conviction of Arthur Andersen. Weissmann had helped persuade the trial judge to advise jurors they could convict the accounting firm regardless of whether its employees had knowingly violated the law.

Writing the court’s decision, Chief Justice William H. Rehnquist noted that the opposing lawyers had “vigorously disputed’’ the jury instructions. The judge, Rehnquist wrote, “failed to convey the requisite consciousness of wrongdoing. Indeed, it is striking how little culpability the instructions required” to convict.

Arthur Andersen never recovered. But when Weissmann stepped down as head of the Justice Department’s Enron task force two months later, he had cemented his reputation for unsparing tactics.

Weissmann not only sought stiff sentences for those convicted in the Enron scandal. As the cases unfolded, he named 114 individuals as “unindicted co-conspirators.’’ In interviews, several defense lawyers complained that by dangling the threat of prosecution over so many prospective witnesses, Weissmann blocked testimony that could have helped their clients.

Defense lawyers also have argued that Weissmann and his colleagues failed to turn over potentially favorable evidence in some cases. The row arose during separate appeals lodged by a top Enron executive and four officials at Merrill Lynch, a financial firm that Enron relied on.

An appellate court ruled that the evidence was not “material’’ enough to have changed the original guilty verdicts. The convictions of three of the Merrill Lynch executives subsequently were overturned for reasons unrelated to the dispute over the evidence.

The episode remains a source of resentment for the defendants and their lawyers.

The evidence would have “contradicted the theory of the government’s case at trial,’’ Sidney Powell, who represented one of the Merrill Lynch executives during his appeal, wrote in her 2014 book, “Licensed to Lie.’’

“Andrew Weissmann is not fit to practice law – much less serve on Mueller’s team,’’ Powell wrote in an email for this article.

Weissmann’s former colleagues, on the other hand, admired what they saw as his relentless push to find and punish those responsible for what was in 2001, the largest bankruptcy in U.S. history.

A former FBI agent who worked on the Enron task force recalled how Weissmann confronted two defense lawyers who appeared to be coaching their client during questioning. After halting the interview and excusing the witness from the room, Weissmann warned both defense lawyers they were opening themselves to potential charges of suborning perjury.

“He was not going to be pushed around,” said the former FBI agent, who spoke on condition of anonymity because his current employer did not authorize him to speak to the news media. “If you want to get to the bottom of the truth – if you want justice – you want Andrew Weissmann as the prosecutor on that case.’’

Even some of Weissmann’s opponents in the Enron case praised his abilities.

Mike DeGeurin, a defense lawyer, lauded Weissmann’s creative efforts to win the cooperation of his clients — Andrew Fastow, who was Enron’s chief financial officer, and his wife, Lea Fastow, a former assistant treasurer at the company.

Andrew Fastow pleaded guilty to conspiracy charges, and his testimony helped convict Enron’s top two executives, Kenneth Lay and Jeffrey Skilling, plus the Merrill Lynch defendants.

DeGeurin said he met with Weissmann up to 20 times to negotiate the Fastows’ plea deals. The prosecutor accommodated the couple’s main request — that their incarcerations be staggered so one parent would always be available for their two young children.

Weissmann allowed Lea Fastow to plead guilty to a misdemeanor, lying on a tax return. DeGeurin said that prevented a judge from sentencing her to more than a year in jail.

“Weissmann was very astute,’’ DeGeurin said. “I felt I was dealing with the top of the food chain.’’

Trump and his lawyers have given mixed signals as to whether the president will consent to questioning. But one of Weissmann’s former targets offered a warning to the White House.

James A. Brown, a former Merrill Lynch executive, said he saw “no reason to hide’’ when Weissmann questioned him before a grand jury 14 years ago.

Brown wound up convicted of perjury and obstruction of justice and served nearly a year in prison. Separate convictions for fraud were overturned on appeal, prompting his release.

“My advice to Trump would be: ‘Do not talk to this guy,’’’ Brown said.

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UPDATES:

11:15 a.m., Feb. 19: This article was updated with details of Gates’ expected plea.

This article was originally published Feb. 16, 3:00 a.m.