Former President Donald Trump’s family business, which is already under indictment in Manhattan, is facing a criminal investigation by another prosecutor’s office that has begun to examine financial dealings at a golf course the company owns, according to people with knowledge of the matter.

In recent months, the district attorney’s office in suburban Westchester County, New York, has subpoenaed records from the course, Trump National Golf Club Westchester, and the town of Ossining, which sets property taxes on the course, a sprawling private club that is perched on a hill north of New York City and boasts a 101-foot waterfall.

The full scope of the investigation could not be determined, but the district attorney, Mimi E. Rocah, appears to be focused at least in part on whether Trump’s company, the Trump Organization, misled local officials about the property’s value to reduce its taxes, one of the people said.

Rocah, a Democrat, has not accused anyone at the company of wrongdoing, and it is unclear whether the investigation is examining Trump’s conduct or if it would ultimately lead to any charges.

In a statement released Wednesday, the Trump Organization said any suggestion that it was inappropriate for the club to seek a lower property tax bill was “completely false and incredibly irresponsible.” Kerry A. Lawrence, a lawyer for the club, declined to comment. The club is one of 16 golf properties the company owns or operates.

Still, the Westchester inquiry intensifies the law enforcement scrutiny on Trump and his family business. Both have been the subject of a long-running criminal investigation by the Manhattan district attorney’s office, which is examining a range of potential financial and tax improprieties.

In July, Manhattan prosecutors charged the Trump Organization and its longtime financial chief, Allen H. Weisselberg, with failing to pay taxes on employee perks like cars and apartments. Trump was not charged in the case, which also involves the New York attorney general, but the investigation is continuing and he remains a subject of it. The prosecutors in that inquiry have sought to pressure Weisselberg into cooperating against Trump.

Trump’s attempts to overturn Georgia’s election results last year are the subject of a separate criminal investigation.

Trump, a Republican, has denied all wrongdoing in the other investigations and has attacked New York’s attorney general, Letitia James, and the Manhattan district attorney, Cyrus R. Vance Jr., both Democrats, for leading what he has called politically motivated witch hunts.

Trump may well adopt a similar stance toward Rocah, who was a senior federal prosecutor in the Southern District of New York before becoming an MSNBC commentator and, at times, openly critical of Trump when he was in office. In late 2019, for example, when Trump was facing impeachment for his actions with Ukraine, she said, “We have a criminal in the White House right now.”

A spokeswoman for Rocah, Jess Vecchiarelli, declined to comment on the investigation.

The Westchester investigation is being led by Elliott B. Jacobson, who spent more than three decades as a prosecutor in the Southern District, much of it in the White Plains office, where he worked with Rocah investigating white collar crime. He came out of retirement in February to work with Rocah’s public corruption bureau and cold case unit before also taking on the Trump golf course investigation, the people with knowledge of the matter said.

Vance, whose case is unfolding separately from the Westchester inquiry, also turned to a hard-charging former federal prosecutor, Mark Pomerantz, for help with his office’s inquiry into Trump. Both Jacobson and Pomerantz, who was most recently a prominent defense lawyer, are working for free.

There is some similarity in the focus of the two investigations, although the Manhattan inquiry is far broader. (Vance and James have also looked into an unrelated private estate in Westchester owned by Trump, but there is no indication that they were examining the golf club or that their investigations overlapped with Rocah’s inquiry.)

Vance is scrutinizing, among other things, whether the Trump Organization manipulated property values to obtain loans and tax benefits; Rocah is questioning the company’s statements about the value of the Westchester golf course, one of the people with knowledge of the matter said.

The value of the property determines the amount of taxes the club must pay to local authorities: the higher the value, the bigger the tax bill.

But after the town of Ossining estimates the value, the club can challenge the assessment — and that is what it has done.

Every year since 2015, the Trump club has appealed its tax bill in court, prompting an outcry in the Ossining area, where hundreds of demonstrators marched in 2017, chanting, “Pay your share.”

In seeking to cut the tax bill — sometimes by as much as 90% — the club has argued that the property was worth much less than Ossining officials had determined, a common strategy among many country clubs, not just Trump’s. In one year, the Trump club put the property’s value at about $1.4 million, while the town assessed it at roughly $15 million.

Rocah’s prosecutors could be comparing the figures the club submitted to Ossining with other statements Trump has made about the property’s value. For example, he declared in federal disclosure forms when he was president that the club was worth more than $50 million.

Yet the method for determining that larger figure is different from how golf courses generally calculate their value for tax purposes. And some golf course operators say that in tax appeals, they routinely propose lower figures to start negotiations with local officials and to protect themselves in case unexpected disasters destroy their properties, not to mislead tax authorities.

This year, after Ossining lost a tax appeal filed by a golf course not owned by Trump, local officials became concerned that he might prevail in court as well. And so, in July, the town announced a compromise with the Trump club, trimming the property’s assessed value by about 30% for the past several years. Collectively, Ossining and other local entities issued the club a refund of about $875,000.

In its statement, the Trump Organization said that the settlement was “amicably resolved” and approved by a host of local officials as well as the judge overseeing the case.

“We believe this settlement is in the best interests of the town’s residents and businesses,” Dana Levenberg, Ossining’s town supervisor, said in a statement, citing the benefit of avoiding what would likely be costly litigation with an uncertain outcome. “Each side compromised in the interest of reaching an agreement,” she said, noting that they settled on values closer to what was “presented by the town than the golf club.”

Levenberg declined to comment on the subpoena the town received from Rocah’s office.

As the Westchester investigation proceeds, Vance’s case against the Trump Organization and Weisselberg, the finance chief, is moving toward a possible trial in August or September, which would coincide with the closing stretch of next year’s congressional elections. The case centers on what prosecutors have described as a 15-year scheme to dole out lucrative off-the-books benefits to employees.

Weisselberg, for example, received a rent-free apartment, tuition for his grandchildren and Mercedes-Benz vehicles for him and his wife, prosecutors say. He avoided paying taxes on $1.7 million of those benefits, according to the indictment, which charged him with grand larceny, tax fraud and other charges.

In a statement, Weisselberg’s lawyers said the indictment against him was “full of unsupported and flawed factual and legal assertions” and that they looked forward to challenging those assertions in court.