He was a personal-injury lawyer who often worked out of taxi offices scattered around New York City.
There was the one above the run-down auto repair garage on West 16th Street in Manhattan, on the edge of the Meatpacking District before it turned trendy. There was the single-story building with the garish yellow awning in the shadow of the Queensboro Bridge. There was the tan brick place on a scruffy Manhattan side street often choked with double-parked taxis.
And then there was his office on the 26th floor of Trump Tower overlooking Fifth Avenue, right next to the one belonging to Donald J. Trump.
Before he joined the Trump Organization and became Mr. Trump’s lawyer and do-it-all fixer, Michael D. Cohen was a hard-edge personal-injury attorney and businessman. Now a significant portion of his quarter-century business record is under the microscope of federal prosecutors — posing a potential threat not just to Mr. Cohen but also to the president.
Mr. Cohen’s businesses are private entities, making it difficult to get a full picture of their finances and operations. But a New York Times review of thousands of pages of public records, and interviews with bankers, lawyers and businessmen who have interacted with Mr. Cohen, reveal the degree to which he has often operated in the backwaters of the financial and legal worlds.
While he has not been charged with a crime, many of his associates have faced either criminal charges or stiff regulatory penalties. That includes partners in the taxi business, doctors for whom he helped establish medical clinics and lawyers with whom he worked.
He has spent much of his personal and professional life with immigrants from Russia and Ukraine. His father-in-law, who helped establish him in the taxi business, was born in Ukraine, as was one of Mr. Cohen’s partners in that industry. Another partner was Russian. And Mr. Cohen used his connections in the region when scouting business opportunities for Mr. Trump in former Soviet republics.
More recently, Mr. Cohen and his father-in-law lent more than $25 million to a Ukrainian businessman who has a checkered financial record and a history of defaulting on loans. And Mr. Cohen long held a small stake in his uncle’s catering hall, which was frequented by Russian and Italian mobsters.
In addition to his legal and taxi businesses, Mr. Cohen has had a seemingly charmed touch as a real estate investor. On one day in 2014, he sold four buildings in Manhattan for $32 million, entirely in cash. That was nearly three times what he paid for them no more than three years earlier.
“This is the type of person you’d see most bankers steer clear of,” said Ben Berzin, a retired executive vice president and senior credit officer at PNC Bank who clashed with Mr. Trump in the early 1990s over loans to the future president’s troubled Atlantic City casinos. The speed with which Mr. Cohen successfully flipped real estate stands out, Mr. Berzin said. “You have to ask what’s going on.”
Robert S. Mueller III, the special counsel investigating Russian interference in the 2016 election, had already been examining Mr. Cohen’s conduct as part of his ongoing inquiry. Last month, federal agents executed search warrants at Mr. Cohen’s home, his office and a hotel room where he was staying. The warrants sought documents related to Mr. Cohen’s business associates, among other things. That investigation, being conducted by the United States attorney’s office in Manhattan, is apparently based on information provided by Mr. Mueller’s team.
Mr. Trump’s lawyers are resigned to the strong possibility that the investigation of Mr. Cohen’s businesses could lead him to cooperate with federal prosecutors.
Mr. Cohen, after being sent a detailed list of questions about his business interests, responded in a text message, “You need to do real fact checking as your questions are totally inaccurate.” Neither he nor his lawyers have offered further comment.
Mr. Trump, for his part, has said that Mr. Cohen was “a good guy” and that federal investigators were “looking at something having to do with his business. I have nothing to do with his business.”
But the president has long entrusted Mr. Cohen to represent him in matters both public and deeply private: real estate negotiations from Fresno, Calif., to the Republic of Georgia, and the hush-money payment to an adult-film actress who said she had had an affair with the future president. Or, as Mr. Trump put it, “this crazy Stormy Daniels deal.”
The $130,000 payment to the actress is in a way emblematic of Mr. Cohen’s many business dealings. Its provenance is murky, obfuscated by a private agreement, pseudonyms and evolving explanations. President Trump said this past week that he had paid Mr. Cohen a retainer that was used to reimburse the $130,000, directly contradicting his earlier statements that he knew of no payment to Ms. Daniels.
Within the Trump Organization, it was Mr. Cohen’s job to deal with Mr. Trump’s thorniest problems. But now, whatever problems investigators find in Mr. Cohen’s own array of businesses could double back on Mr. Trump.
The son of a Holocaust survivor, Mr. Cohen grew up in the Five Towns area of Long Island, just east of the New York City borough of Queens. It was a comfortable life — both his father and an uncle were doctors, and he attended a local private school then called Woodmere Academy.
“My cousins are all either lawyers or doctors,” Mr. Cohen told The New York Times last year.
One of those relatives was his uncle Dr. Morton W. Levine. Uncle Morty, as he was known to his family, had no children of his own, and he and Mr. Cohen were close. He even let his nephew drive his Bentley.
Dr. Levine, a family practitioner, provided medical assistance to members of the Lucchese crime family, “which aided their illegal activities,” according to a sworn affidavit in 1993 from an F.B.I. special agent. The agent was involved in the investigation of the Lucchese underboss, Anthony (Gaspipe) Casso, who “regarded Levine as someone who would do anything for him,” according to the affidavit. That account was buttressed by testimony from a longtime Lucchese associate in an unrelated 2006 federal trial. In 1992, Dr. Levine bought Mr. Casso’s home while Mr. Casso was a fugitive. Dr. Levine has acknowledged in court documents that Mr. Casso was a patient. But he said he did not know that the house belonged to Mr. Casso and denied any wrongdoing.
Dr. Levine also owned El Caribe, a Brooklyn catering hall that for decades was the scene of mob weddings and Christmas parties. Two of New York’s most notorious Russian mobsters once maintained offices there.