David Petraeus hires Sarah Palin's lawyer to navigate his fall from grace

The lawyer, Robert Barnett of Williams & Connolly, is known for negotiating book deals for the political elite, from President Barack Obama to one-time vice presidential candidate Sarah Palin.

Mr Barnett will help Mr Petraeus as he exits government, according to Reuters news agency, which confirmed a Politico report.

The Central Intelligence Agency, the Justice Department and Congress are investigating Mr Petraeus' conduct over the extra-marital affair with his biographer, Paula Broadwell.

In that time, he has built an unconventional practice representing best-selling authors, political leaders, television news correspondents and other high-profile clients.

In addition to Mr Obama and Mrs Palin, other authors he has represented include novelist Mary Higgins Clark and entertainer Barbra Streisand.

He has also helped former government officials from across the political spectrum navigate their return to private life, including former US presidents Bill Clinton and George W Bush, former secretary of state Madeleine Albright, and former members of Congress.

He joined Williams & Connolly in 1975 and became a partner in 1978.

Source: Reuters