Former CIA Director John Brennan has been subpoenaed to testify next month before a grand jury in Florida, as part of a sprawling Justice Department investigation into whether former intelligence officials conspired against President Donald Trump. 

Brennan's defense attorney Ken Wainstein said in a court filing that the former CIA chief had been asked to appear on October 15 before a grand jury in Fort Pierce, Florida.

The subpoena relates to a ‘far-reaching’ criminal probe investigating whether federal government officials conspired to deprive Trump of his civil rights - spanning back to his first term.

The case centers on whether Obama-era officials conspired to create the conspiracy that the Trump campaign illegally worked with Russia ahead of the 2016 election - which has since been widely debunked.

It also includes charges against Trump after the January 6, 2021 Capitol riot and after the bombshell Mar-a-Lago classified documents case. Those lawsuits were formally dropped against Trump after his re-election in 2024.

Brennan is reportedly a ‘subject’ of that broader probe, though apparently not the main target. 

Prosecutors said Brennan also remains a 'target' of another probe, investigating whether he knowingly made false statements to a House committee in 2023 about the intelligence community's assessment that Russia sought to aid Trump in the 2016 presidential election - an allegation Brennan has vehemently denied.

News of the subpoena did little to answer mounting public questions about the so-called ‘grand conspiracy’ probe in southern Florida - though answers began to emerge about who will oversee the sprawling effort following the abrupt departure of a top Trump-aligned prosecutor last week.

A spokesperson for the Justice Department told the Daily Mail Monday that Jason Reding Quiñones, the US Attorney for the Southern District of Florida, will be overseeing the probes in Florida, 'along with the many prosecutors' in the district who have been working on the investigation. 

They are working with support from DOJ's headquarters in DC, they said.

The Senate confirmation of Attorney General Todd Blanche earlier this year had been praised as a shot in the arm for the so-called ‘grand conspiracy’ investigation. 

Insiders told the Daily Mail that Blanche had tapped former federal prosecutor and longtime Trump loyalist, Joe diGenova, to take the reins of the investigations earlier this year, after career prosecutors had failed to make headway. 

The delays frustrated Trump and were in part behind his decision to fire Pam Bondi as attorney general, several sources familiar with her departure said.

But diGenova did not make the headway he had been expected to make - at least, not in the ambitious time frame some in Trump’s orbit had hoped - and last week, he abruptly announced his resignation.

Recent news reports suggested diGenova's abrupt departure was in part due to the pressure he was facing from DOJ leaders to move more quickly in prosecuting Trump's most outspoken political foes. 

But it was not immediately clear to what degree that impacted diGenova's decision to resign. 

A DOJ spokesperson told the Daily Mail last week they are 'grateful to Joe diGenova for his many years of service to the Department.'

'The Attorney General thanks him for his work these past five months alongside the great team of experienced prosecutors in the Southern District of Florida, led by U.S. Attorney Jason Reding Quiñones,' the spokesperson added. 

Speaking in federal court Monday as part of a separate lawsuit filed by Brennan to preserve government records in the two DOJ investigations involving him, Wainstein described diGenova’s exit from DOJ as ‘pretty remarkable.' 

Still, he stressed to the court that there is still a viable threat of prosecution hanging over his client.

‘There’s a lot of really underhanded stuff going on in this investigation,’ Wainstein said of the conspiracy investigation, which is examining at least some actions that took place 10 years ago.