WASHINGTON - The woman caught up in the scandal that brought down CIA director David Petraeus said Tuesday she decided not to press charges against his mistress over allegedly threatening emails.

The scandal erupted last year after Jill Kelley, a wealthy Tampa, Florida socialite, complained to the FBI that she had received menacing emails from an anonymous sender.

The emails turned out to be from Paula Broadwell, an Army reservist who had written a glowing biography of Petraeus's tenure as a top military commander.

Authorities then stumbled upon evidence of Broadwell's affair with Petraeus, as well as exchanges between Kelley and the four-star officer in charge of the war in Afghanistan, General John Allen. Kelley said the media frenzy over the case had been a nightmare for her family and denied she had any romantic relationship with General Allen. Although she alleged Broadwell's emails amounted to a bid to "blackmail" her, Kelley said she chose not to press charges against Petraeus's biographer.

In the emails sent by Broadwell, "there was blackmail, extortion, threats," Kelley told The Daily Beast's media reporter Howard Kurtz, in her first interview since the scandal broke.

"I knew I was being stalked," she said.

She declined to speculate on Broadwell's motives and also said she found media reports that the two were romantic rivals "bizarre."

But though she was frightened and turned to an FBI friend for help, she opted against pushing for charges against Broadwell.

Kelley said she was concerned how the case would affect her friends and their families. "I just wanted to let them move on with their lives and not have to relive it," she said.

She also dismissed allegations she had exchanged thousands of emails with General Allen, whose correspondence with Kelley is the subject of an investigation by the Defence Department's inspector general.

Kelley said she believes the number of emails with Allen were in the hundreds and not thousands and denied she had any romantic relationship with the general, who is soon to step down from his post in Kabul. But she declined to release the emails she exchanged with Allen.

Kelley, who is married to an oncologist in Tampa, Florida, volunteered as a "social liaison" organising events at nearby MacDill Air Force Base, home to US Central Command (Centcom).

From October 2008 until the summer of 2010, Petraeus was head of Centcom and the Petraeus and the Kelley families became friends.