The “threatening” emails sent by Paula Broadwell to Florida socialite Jill Kelley – that eventually uncovered Broadwell’s affair with David Petraeus – vowed to make her perceived rival “go away”, it has been claimed.

The messages sent to Jill Kelley, who contacted the FBI after receiving them in May, were so menacing that the military party planner feared for her life, according to a friend.

The friend, who has not been identified, said that Jill Kelley, a military party planner in Tampa, had called her to seek advice after receiving the messages and read them out over the phone.

Speaking to the New York Daily News, she described the messages as much more threatening than originally reported, adding: “Any normal person who got emails like that would have immediately called police.”

In the messages, which were sent anonymously, Paula Broadwell promised to “make you go away” and boasted about her military background and having “powerful” friends, the Daily News reported.

“This wasn’t just a case of cyber-bullying,” the friend said.

“[Jill Kelley] was scared for her life. She had reason to be. These emails are the real thing. When she read them to me, I literally had the shivers.”

The Wall Street Journal previously reported that, in one email, Paula Broadwell had accused Jill Kelley of touching “him” underneath a table and asked if Kelley’s husband was aware of her actions.

In another, Paula Broadwell asked: “Who do you think you are?”

The threatening emails sent by Paula Broadwell to Florida socialite Jill Kelley vowed to make her perceived rival go away

Paula Broadwell also accused Jill Kelley, a David Petraeus family friend, of “parad[ing] around the base”, adding: “You need to take it down a notch.”

But the threatening emails, which had previously been described as “cat-fight stuff”, led to Paula Broadwell’s undoing after Jill Kelley contacted a friend in the FBI about the messages.

The anonymous emails contained classified information about David Petraeus’ whereabouts and, thinking there had been a potential national security breach, the FBI was forced to investigate.

During their probe, they traced the emails back to Paula Broadwell and also uncovered emails revealing her months-long affair with CIA boss David Petraeus, whose biography she had penned.

But investigators also found tens of thousands of emails between Jill Kelley and General John R. Allen, head of U.S. troops in Afghanistan, and deemed some “inappropriate” and “flirtatious”.

General John Allen, a married father of two, is now under investigation, but both he and Jill Kelley deny any wrongdoing.

Jill Kelley has also denied being any more than friends with David Petraeus and released a statement saying: “We and our family have been friends with Gen. Petraeus for over five years. We respect his family’s privacy and want the same for us and our three children.”

Jill Kelley’s twin sister sister, Natalie Khawam, has also been dragged into the scandal, with reports detailing her troubled child custody battles and shrewd socializing skills. Celebrity attorney Gloria Allred is now representing her.

The latest revelations about the contents of the emails – which eventually led to David Petraeus’ resignation from the CIA on November 9 – come as Paula Broadwell moved back home with her husband and children.