NEW YORK (AP) — Manhattan prosecutors postponed a scheduled grand jury session Wednesday in the investigation into Donald Trump over hush money payments during his 2016 presidential campaign, at least temporarily slowing a decision on whether to charge the ex-president, according to four people familiar with the matter.

The grand jurors were told to be on standby for Thursday, another day when the New York panel has been meeting, three of the people said. When the grand jury next meets, it may hear from yet another witness, according to a person familiar with proceedings that appear to be nearing a decisive vote on whether or not to indict Trump.

The reason for the cancellation of Wednesday’s sessions was not immediately clear, though one person said it was not security-related.

The panel has been hearing from final witnesses, even as Trump himself has been railing against the investigation and claiming his arrest is imminent. Law enforcement officials have accelerated security preparations in the event of unrest accompanying an unprecedented charge against a former U.S. president.

The people who confirmed that the grand jury would not meet as scheduled weren’t authorized to discuss details on the record and spoke on condition of anonymity to The Associated Press. The district attorney’s office declined to comment on the development, which was earlier reported by Business Insider.

The postponement comes amid mounting signs that the grand jury is nearing the completion of its work. The panel is probing Trump’s involvement in a $130,000 payment made in 2016 to the porn actor Stormy Daniels to keep her from going public about a sexual encounter she said she had with Trump years earlier.

Trump has denied the claim, insisted he did nothing wrong and has attacked the investigation, led by Manhattan District Attorney Alvin Bragg, as politically motivated.

Prosecutors had recently invited Trump himself to appear before the grand jury, and on Monday heard from a witness favorable to his case as a way to ensure that the panel would be presented with any information that could conceivably be considered exculpatory.

Trump over the weekend stated that he expected to be arrested on Tuesday, though the day came and went without that happening.