MIAMI (AP) — Former President Donald Trump and his aides are bracing for a potential indictment in the classified documents investigation as prosecutors handling the probe were spotted Thursday at a Miami courthouse where a grand jury has been hearing from witnesses.

The former president's lawyers have been told he is a target of the investigation, the clearest indication yet that criminal charges could be coming soon, according to one person familiar with the matter. In an effort to get ahead of a potential indictment, aides over the last two days have been reaching out to Trump allies in Congress to be prepared to go on television and offer defenses of the former president, according to another person familiar with the matter.

Both people requested anonymity to discuss matters related to the secretive grand jury process.

Meanwhile, a grand jury in Miami heard from at least one additional witness this week — a former top aide to Trump — as signs continued mounting that prosecutors were building toward a potential indictment related to the handling of hundreds of classified documents at Trump's Florida home, Mar-a-Lago.

On Monday, his lawyers met with Justice Department officials in Washington to argue against an indictment, exiting the building less than two hours later without commenting. Trump, meanwhile, has issued social media posts this week suggesting he anticipates being charged and has escalated attacks on special counsel Jack Smith and his team. And a key prosecutor on the team, David Harbach, was spotted by an Associated Press journalist outside the courthouse on Thursday.

The notification to Trump's lawyers that he is a target is especially ominous given that such a warning often, though not always, precedes criminal charges. The Justice Department defines a target as someone whom prosecutors have substantial evidence linking to a crime.

"The signal is increasingly that the charges against the former president will be in Florida," said Brandon Van Grack, a former Justice Department prosecutor and a key lawyer on an earlier special counsel team that investigated ties between Russia and the 2016 Trump campaign.

Lawyers for Trump did not return calls seeking comment. A Trump spokesman would not confirm or deny receiving a letter and a Justice Department spokeswoman declined to comment.

On Wednesday, Taylor Budowich, who had served as a spokesman for Trump after his presidency and now runs a pro-Trump super PAC, testified before the grand jury. He confirmed his appearance on Twitter, writing, "Today, in what can only be described as a bogus and deeply troubling effort to use the power of government to 'get' Trump, I fulfilled a legal obligation to testify in front a federal grand jury and I answered every question honestly."

A variety of witnesses, including lawyers for Trump, close aides to the former president and officials with the Trump Organization, have appeared over the past year before the grand jury in Washington as part of a Justice Department special counsel investigation into 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.

But the existence of a separate grand jury in Florida adds a wrinkle to an investigation that has been largely shrouded in mystery and has been thought to be in its end stages. It suggests that prosecutors may be moving toward bringing criminal charges in Florida, where the documents were taken after Trump left the White House and where multiple acts of alleged obstruction have occurred, instead of in Washington.

Though the bulk of the investigative work has been done in Washington, prosecutors could simply read key testimony to the Florida grand jury or have a summary witness summarize all the key evidence, Van Grack said.

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. After that meeting, Trump posted on his Truth Social platform in capital letters, "How can DOJ possibly charge me, who did nothing wrong," when no other presidents have been charged.

He also called into a radio show, where he confirmed the meeting with his lawyers and said: "Well, I can just say this: They did go in and they saw 'em and they said very unfair. No other president has ever been charged with anything like this.'"

On Wednesday, he issued a new social media post saying, "No one has told me I'm being indicted, and I shouldn't be because I've done NOTHING wrong, but I have assumed for years that I am a Target of the WEAPONIZED DOJ & FBI."

Trump's super PAC has been distributing talking points denouncing Smith and painting him as intent on targeting Trump. A veteran public corruption and war crimes prosecutor, Smith was selected in November to serve as special counsel. As former chief of the Justice Department's public integrity section, he oversaw investigations into multiple prominent Democrats, a track record that likely insulates him from attacks from Trump allies that he's a partisan prosecutor.

The investigation has focused 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 with classification markings.

Beyond the Mar-a-Lago investigation, another probe in Washington also conducted by Smith centers on efforts by Trump and his allies to undo the results of the 2020 presidential election.

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Colvin in Des Moines, Iowa, contributed to this report. Associated Press journalists Adriana Gomez Licon and Daniel Kozin also contributed.

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