The legal fight over New York City’s first-ever two-year rent freeze for roughly 1 million stabilized apartments grew heated Tuesday as the city’s top attorney threatened to call his adversary former First Deputy Mayor Randy Mastro to the witness stand, and as Mastro asked the judge to grant him more access to city officials’ phones.

New York City Corporation Counsel Steven Banks raised the possibility of questioning Mastro under oath after Mastro – who now represents a group of landlords attempting to overturn the rent freeze – argued that City Hall’s communications with the board responsible for the rent freeze decision were “not normal” and evidence of an influence campaign.

“The allegations that Mr. Mastro is the arbiter of what is normal is going to result in us asking for a hearing to examine Mr. Mastro about what was normal during his tenure as the first deputy mayor and the contacts between his administration and the [Rent Guidelines Board],” Banks told Manhattan Judge Brendan Lantry.

Banks also criticized what he called Mastro’s “insults” and “bravado.”

Mastro has accused Mayor Zohran Mamdani and other top city officials of meddling in the Rent Guidelines Board’s June decision to secure a rent freeze. Mamdani has sharply denied that he or his administration dictated the vote.

Banks’ attempt to turn the tables on Mastro comes two weeks after Gothamist reported on how Mastro himself spoke with Doug Apple, the Rent Guidelines Board's chair at the time, in the lead-up to the board’s vote in 2025. Apple told Gothamist that Mastro advocated for a limited increase in phone conversations while serving as first deputy mayor under Mayor Eric Adams. The board voted to raise rent by 3% on one-year leases that year.

Mastro said he did talk with Apple but only to say why Adams disagreed with the board’s decision.

The nine-member Rent Guidelines Board’s determines how much landlords can raise the rent on new one- and two-year leases for rent-stabilized apartments each year. Though members are appointed by the mayor, the Rent Guidelines Board is considered an independent body tasked with considering financial data and public testimony.

In court Tuesday, Mastro cautioned that Banks “be careful what he wishes for” should he attempt to question him under oath, because he would then attempt to question current Deputy Mayor Leila Bozorg and other city officials about their own communications with board members and staff.

“This isn't about what happened in 2025,” Mastro said in court. “But there is of course a world of difference between an independent RGB telling the mayor's office we're not doing what you want, we're going to impose higher rent increases and what happened here, which is an obedient RGB reporting to City Hall at every stage.”

Lantry, however, threw cold water on the fiery back and forth, telling the attorneys he had no plans of hearing testimony in a lawsuit over whether the board ignored data on rising landlord costs to deliver Mamdani’s “freeze the rent” campaign pledge.

Lantry had previously ordered city lawyers to turn over communications that Mamdani and 12 other city officials had with staff and appointees of the Rent Guidelines Board. The city provided images of texts and emails that primarily focused on new appointments to the board and its meeting schedules, according to records filed with the court, but that did not appear to show outright attempts to influence board decision-making.

Mastro told Lantry that a more thorough analysis might turn up more details – including the use of the encrypted messaging app Signal, that Mamdani administration officials have employed in other instances.

“There are things that may not have been caught in just this screenshot search,” Mastro said. “There's the potential to recover information that has been deleted, and this City Hall has used Signal and acknowledged they use Signal so that things would be automatically deleted.”

Mamdani administration officials used Signal for a group chat with online influencers aligned with his politics, with messages scheduled to delete after a certain period of time.