WASHINGTON (AP) — Federal prosecutors are using a grand jury in Florida as part of their investigation into the possible mishandling of classified documents at former President Donald Trump’s Palm Beach property, a person familiar with the matter said Tuesday night.

The grand jury is in addition to a separate panel that has been meeting in Washington for months to consider charges against Trump over the retention of hundreds of classified documents at Mar-a-Lago and potential obstruction of the government’s efforts to reclaim the records.

It is not clear why prosecutors are using an additional grand jury, which was described to The Associated Press by a person who insisted on anonymity to discuss secret proceedings, or which witnesses might be testifying before it.

A variety of witnesses, including lawyers for Trump, close aides to the former president and officials with the Trump Organization, have appeared over the last year before the grand jury in Washington. But the use of a different grand jury in Florida suggests that prosecutors may also be eyeing at least some potential charges in that state.

The Mar-a-Lago investigation, being led by special counsel Jack Smith’s team of prosecutors, is thought to be in its final stages, with a charging decision expected soon. Trump’s lawyers met at the Justice Department on Monday with officials including Smith, part of an effort by the legal team to raise concerns about what they say is prosecutorial misconduct and to try to argue against a potential indictment.

The investigation has centered not only on the possession of classified documents, including at the top-secret level, but also on the refusal of Trump to return the records when asked and on possible obstruction. The FBI last year issued a subpoena for classified records at the property, and after coming to suspect that Trump and his representatives had not returned all the documents, returned with a search warrant and recovered an additional 100 documents with classification markings.

Investigators have questioned a Trump associate who was seen on surveillance camera moving boxes of documents at Mar-a-Lago. As part of an obstruction probe centered in part on surveillance footage, they more recently have expressed interest in a worker’s draining of a pool at the resort last October, an act that caused a flood at the property, according to another person who spoke on condition of anonymity. That area of interest was first reported by CNN.

A spokesman for Smith declined to comment Tuesday night on the existence of another grand jury.