CHARLOTTE, North Carolina (Reuters) - Paula Broadwell, the biographer whose affair with former CIA chief David Petraeus led to his resignation, has hired a high-profile Washington communications firm, Glover Park Group, to represent her, a source familiar with the arrangement said on Monday.

Glover Park's consultants include well-known names such as Dee Dee Myers, who served as White House press secretary during President Bill Clinton's first term.

WPP Plc, the world's largest advertising group, bought Glover Park last year.

Broadwell's hiring of Glover Park was reported by AdAge. The firm did not respond to requests for comment.

Anonymous emails that Broadwell sent to Jill Kelley, a Tampa, Florida socialite who knew Petraeus, prompted an FBI investigation that exposed Broadwell's affair with Petraeus, a retired U.S. Army general known for his success in the Iraq war.

Broadwell is under investigation for her handling of classified materials, although both she and Petraeus have separately told investigators they did not share security secrets.

FBI agents found a substantial amount of classified information on Broadwell's personal computer when they searched her home with her consent last week, according to law enforcement and national security officials.

Sources briefed on the investigation told Reuters the documents date from before August 2011, when Petraeus took up his post at the CIA and the two started their affair. None of the material comes from the CIA, the sources said.

As an Army reserve officer involved in military intelligence, Broadwell had a security clearance that allowed her to handle sensitive documents. However, she would still have to comply with strict rules that lay out how sensitive materials must be protected.

Broadwell's security clearance has now been suspended. She could have it revoked and face harsher penalties if it is found that she mishandled classified data.

Broadwell returned to her home in Charlotte, North Carolina, on Sunday for the first time since the scandal erupted on November 9 with Petraeus's sudden resignation. Along with her husband and two children, she was greeted by close friends and neighbors.

"It's tough," said neighbor Sarah Curme. "Her primary focus is her husband and her kids. I think that's where they are now."

Glover Park is the latest high-profile adviser hired by a figure in the scandal.

Kelley is being represented by one of Washington's most prominent trial lawyers, Abbe Lowell, a family friend who has represented former U.S. Senator John Edwards and disgraced Republican lobbyist Jack Abramoff.

Kelley also has enlisted Judy Smith, a well-known crisis PR manager who is the model for the ultra-effective fixer and spin doctor Olivia Pope in the ABC TV drama "Scandal."

Kelley's twin sister, Natalie Khawam, has retained celebrity lawyer Gloria Allred and the pair plan to hold a news conference in Washington on Tuesday to "explain Natalie's relationship with General Petraeus and his wife Holly."

Petraeus has hired Washington lawyer, Robert Barnett of Williams & Connolly LLP, to help him navigate the fallout from his career-ending affair with Broadwell.

Barnett is known for negotiating book deals for the political elite, from President Barack Obama to one-time vice presidential candidate Sarah Palin.