Paula Broadwell and David Petraeus pictured together at an intelligence event after they learned of FBI probe

David Petraeus and his mistress Paula Broadwell were seen chatting together at a high-profile intelligence event weeks after they learned the FBI had launched an investigation into their affair, it has been claimed.

Their brazen appearances at the annual Office of Strategic Services Dinner in Washington D.C. on October 27 came just two weeks before David Petraeus’ dramatic resignation last Friday.

A photograph shows Paula Broadwell at the event, according to NBC sources, and guests noted she was confident – rather than a woman under investigation for potential national security breaches.

“It’s mind-boggling that she could be so reckless as to show up at high-profile events like this, shortly after learning the FBI was investigating their affair,” one former U.S. intelligence official told NBC.

The probe was launched in May after Paula Broadwell sent anonymous threatening emails to Florida military socialite and perceived love rival Jill Kelley, telling her to “back off” from David Petraeus.

The catty emails were traced back to Paula Broadwell and, in the process of the investigation, agents also uncovered messages revealing the affair between the biographer and David Petraeus.

A friend claims the affair ended in July and agents interviewed Paula Broadwell during the week of October 14 and David Petraeus the week of October 21, CNN reported – just days before the Washington event.

Paula Broadwell and David Petraeus did not sit together, but were seen speaking, sources told NBC.

Some attendees claimed they attended the event together, conservative weekly Human Events reported, but others disputed this.

It is the last known meeting of the pair who seemed very much at ease with each other, despite claiming their affair had ended months prior.

Paula Broadwell, a married mother of two who first met David Petraeus as he spoke at Harvard University in 2006, appeared confident while speaking with guests, Fox News reported.

“She was elated, beaming that night,” the source said.

“She was having her picture taken with guests. She would disappear for a few minutes and then return, very much enjoying the attention.”

They added that Paula Broadwell spoke openly about David Petraeus and had personal insights and opinions about him.

“She said he was unsure of himself sometimes,” they said.

David Petraeus, who is also married with two children, was described as being in a “great mood” and gave a speech honoring a CIA director predecessor and Secretary of Defense Robert Gates.

After the event, one of the most high-profile events within the intelligence community, the FBI interviewed Paula Broadwell for a second time.

On November 6 – Election Day – the FBI told Director of National Intelligence James Clapper about the probe during a phone call. He then spoke with David Petraeus and advised him to resign.

On November 8, President Barack Obama was told about the 10-month affair and Petraeus visited him at the White House to hand in his resignation.

Barack Obama accepted David Petraeus’ resignation and he stepped down as the head of the CIA on November 9.

The scandal later dragged in another general, the U.S. Commander in Afghanistan, General John Allen, after the FBI investigated Jill Kelley’s emails from Paula Broadwell.

During the probe, they reportedly uncovered 20,000 to 30,000 pages of email correspondence between General John Allen and Jill Kelley, an unpaid social liaison who throws parties for military in Tampa, Florida.