During an interview with 60 Minutes, to be broadcast Sunday, ex Hewlett-Packard chairman Patricia Dunn may have provided some clues about her upcoming defense against felony charges she allegedly participated in an illegal investigation.

According to excerpts of the interview, released by CBS yesterday, she launched the probe “at the request of this board to solve a serious problem.”

“If you think that Hewlett-Packard is the only company that has an investigations force — which by the way, is peopled mostly with former law enforcement officers that do all kinds of private detective work, monitoring, posing as other people in order to solve problems to protect shareholder value — you’re being naive,” she reportedly told the famous network news program.

To me, that suggests that her lawyers will argue that everything she did was grounded in the principle that her legal duty to H-P stockholders superseded most (any?) other behavior.

If that’s indeed what she asserts, however, we can expect the counter argument that by participating in or explicitly or implicitly approving criminal activity, she was risking greater damage to the company’s value than any leaks could have incurred. Prosecutors could then plot H-P’s stock, which rose from under $19 a share 22 months ago to more than $36 on Sept. 5, the day before California’s attorney general announced an inquiry into the Palo Alto computer giant. In the month since, the stock has fluttered between $34 and $38 a share as investors ride the daily rollercoaster of revelations and implications.