Petraeus 'shared no classified information'
13 November 2012 Last updated at 18:14 GMT
One of the most senior generals in the US military has been linked to a woman involved in the downfall of CIA Director David Petraeus.
Afghanistan commander Gen John Allen is being investigated regarding reports he sent thousands of "inappropriate" emails to Florida socialite Jill Kelley.
The episode raises questions about whether the personal relationships of men in such positions has given unauthorised people access to classified material.
Dr John Nagl, himself a former US General, was a cadet under Gen Petraeus 25 years ago. He told the BBC's PM programme the general had been a "trusted career guide, role model, exemplar" for many years.
He said he had been in contact with the General via email in recent days, and "I am assured that he shared no classified information with Paula... I don't think there's any real concern there."