The Manhattan district attorney is delving deeply into the personal and financial affairs of the chief financial officer for former president Donald Trump’s company, probing the extent of Allen Weisselberg’s loyalty to Trump and scrutinizing a Trump-owned apartment once occupied by Weisselberg’s son, according to people familiar with the investigation.

This questioning is now led by a former mob prosecutor, and one person familiar with the investigation said it is aimed at “flipping” Weisselberg — attempting to turn one of Trump’s longest-serving and most important aides into a witness against him.

Cyrus R. Vance Jr. (D), Manhattan’s top prosecutor, has not formally accused anyone of wrongdoing, including Trump, Weisselberg or the latter’s family. But the focus on Weisselberg underscores the depth and ambition of Vance’s inquiry, a criminal investigation broader than any Trump’s company is known to have faced before.

Vance’s focus on Weisselberg has included questions related to two of his adult children, a tactic that could be an effort to increase pressure on the elder Weisselberg. One of Weisselberg’s sons also works for the Trump Organization, where he manages the company’s Central Park ice rinks. Another Weisselberg son works for a company that has extended loans to the Trump Organization.

The Manhattan District Attorney's Office has taken possession of former president Donald Trump's tax returns, officials said Feb. 25. (Reuters)

Vance recently obtained millions of pages of Trump’s tax and financial records. Now he appears to be focused on their human equivalent: a man who has paid Trump’s bills and kept his books since the 1980s.

Weisselberg has been CFO since 2000 and has said he handles nearly all the company’s financial transactions. He once described himself in a deposition as Trump’s “eyes and ears . . . from an economic standpoint.”

“Allen is in charge of everything,” said one former Trump employee, who spoke on the condition of anonymity because of the sensitivity of the matter, as did several people familiar with the investigation.

Vance declined to comment for this report. So did the Trump Organization and Mary Mulligan, an attorney for Weisselberg.

Typically, efforts to flip witnesses have two parts: First, prosecutors work to build evidence that a witness may have their own legal liabilities. They then try to convince the witness to save themselves by turning on a higher-up.

The person with knowledge of the case said investigators were trying to “cast a wide net . . . looking to shake the tree a little bit.”

In this case, prosecutors have scrutinized Weisselberg’s work in helping to assess the value of Trump buildings as the company sought to obtain loans or property-tax reductions, people familiar with the investigation said. They have also asked about a Trump-owned luxury apartment where Weisselberg’s son Barry lived for several years. The exact nature of Vance’s interest in the apartment is not known, but if Barry Weisselberg, who manages Trump’s ice skating rinks, got the apartment rent-free, that might be considered a fringe benefit of his job and subject to income tax.

Two people with knowledge of the district attorney’s probe said the team has also been analyzing the finances of the cash-only skating rink where Barry Weisselberg works.

At the same time, investigators have asked detailed questions about Allen Weisselberg’s financial history and his feelings about Trump, according to people familiar with the investigation.

“All the real estate that he’s had. Every house, every car, every perk. The way his lifestyle goes. Is he frugal? Is he generous?” one of the people recounted, listing investigators’ questions about Allen Weisselberg. “What’s his relationship with Donald? . . . How loyal is each person to each other?”

A person familiar with thinking at the Trump Organization said company executives are confident their practices for assessing the value of property fall within industry norms for New York City. The person also said there is broad confidence in Weisselberg’s loyalty.

Trump is now facing two wide-ranging probes of his financial practices: Vance’s inquiry and a separate civil investigation by New York Attorney General Letitia James (D).

The district attorney’s criminal investigation began in 2018 and focused initially on hush-money payments that Trump attorney Michael Cohen made just before the 2016 election to women who claimed they had affairs with Trump.

Since then, however, his investigation has expanded to cover a wide swath of Trump’s financial activity before the presidency. Vance has subpoenaed records from a variety of sources, according to documents and officials: Trump’s insurance brokers, his lenders, property-tax authorities in New York, even planning and zoning records from a small town that includes a Trump-owned mansion.

Trump has called both inquiries politically motivated. After the Supreme Court last month allowed Vance to obtain his taxes, the former president called the investigation a “fishing expedition.”

People familiar with Vance’s inquiry say it has taken on new urgency since the recent hiring of Mark F. Pomerantz — an attorney who prosecuted Gambino crime family boss John Gotti’s son in the 1990s — on a special assignment.

Vance has sat in on recent interviews, conducted virtually because of the coronavirus pandemic, but let Pomerantz lead the questioning, people familiar with the investigation said.

In those sessions, Pomerantz has focused on Weisselberg, asking wide-ranging questions about the accountant, in an apparent effort to build a broader profile of the longtime Trump employee. The recent focus on Weisselberg was first reported by the New York Times.

“Have you ever met his wife?” one witness was asked recently, according to a person familiar with the investigation. “Have you ever been to his home?”

Investigators have also asked about the apartment in the Trump Parc East building, on Central Park South, where Barry Weisselberg lived for several years. Jennifer Weisselberg, Barry Weisselberg’s ex-wife, told Bloomberg News last year that the couple lived there free. She said she believed at the time the apartment was a wedding gift from Donald and Melania Trump. This week, a spokesperson for Jennifer Weisselberg declined further comment.

City property records show the unit belonged to a Trump-owned entity, Trump CPS LLC. The company later sold the unit in 2014 for $2.8 million.

IRS rules say that if an employer provides an apartment rent-free, it typically should be considered part of the employee’s compensation and subject to income tax. There are exceptions, but they are aimed at people such as live-in maids and building superintendents, who live where they work and are constantly on call. It is not known how Barry Weisselberg or the Trump Organization treated the apartment for tax purposes.

A person familiar with the investigation said prosecutors have been examining portions of Barry Weisselberg’s tax returns.

The Trump Organization did not respond to questions about the apartment. Barry Weisselberg did not respond to a request for comment; his brother, Jack Weisselberg, told The Washington Post he was declining comment for both of them.

Investigators have also asked witnesses about loans made to the Trump Organization by Ladder Capital Finance — Jack Weisselberg’s employer, according to people familiar with the investigation. As part of that process, lenders typically ask about the financial health of the buildings, including the occupancy level and the total rent paid by tenants.

Ladder Capital has loaned the Trump Organization more than $270 million, related to four buildings in Manhattan. The loan documents were signed by other Ladder Capital executives, not Jack Weisselberg.

Neither Ladder Capital nor the Trump Organization has responded to questions asking if Jack Weisselberg played a role in obtaining the loans.

It is unclear what testimony, if any, Allen Weisselberg has provided to Vance’s office.

In the past, however, Weisselberg has provided testimony to government investigations into Trump’s financial dealings.

In 2017, Weisselberg spoke to investigators for a New York attorney general investigation of Trump’s charity, the Donald J. Trump Foundation. He told them that the charity’s board never met, that the charity had “no policy” for determining whether its spending followed nonprofit laws, and that the charity had been co-opted by Trump’s 2016 presidential campaign, in violation of a ban on mixing charities and politics.

The attorney general later used Weisselberg’s testimony against Trump, in a lawsuit that ended with a New York judge ordering Trump to pay a $2 million penalty.

And Weisselberg also accepted a deal from federal prosecutors focused on Cohen’s hush-money payments, in which Weisselberg testified about others in exchange for immunity for himself. Prosecutors were interested in the Trump Organization’s reimbursement of Cohen for the hush-money payments.

Cohen later pleaded guilty to two felony counts related to those payments. He was sentenced to prison but was released to home confinement last year because of concerns about the coronavirus pandemic.

On Twitter this week, Cohen seemed to relish the idea that Weisselberg was facing new scrutiny, after putting so much scrutiny on him.

“Remember that Allen Weisselberg received (federal) immunity from the SDNY to provide information and testify against me for the @StormyDaniels payment,” he wrote on Tuesday, adding the hashtag “#KarmaBoomerang.”

Alice Crites contributed to this report.