SAN JOSE, Calif. — A congressional panel wants to question key figures in the scandal surrounding Hewlett-Packard Co.'s investigation of media leaks, while a shareholder lawsuit was filed in state court accusing the company's top brass of breaching their duties.

The House Energy and Commerce Committee sent letters Friday requesting that HP Chairwoman Patricia Dunn and General Counsel Ann Baskins appear at a Sept. 28 subcommittee hearing.

HP spokesman Mike Moeller declined to say whether either would testify.

"HP is fully cooperating with all ongoing investigations and inquiries, including the one being conducted by the House subcommittee," he said.

Noted Silicon Valley attorney Larry Sonsini, who served as an outside legal adviser to HP during its investigation, was also asked to appear, as was Ronald DeLia, who runs a Boston-area private investigation firm that was hired by HP to conduct the probe.

Calls to Sonsini and DeLia were not immediately returned.

Commerce's Oversight and Investigations Subcommittee has been conducting an inquiry into "pretexting" — the practice of impersonating people in order to access their personal information.

Dunn has acknowledged that she authorized the probe in which private investigators hired by HP used Social Security numbers and other personal information to pose as company directors, employees and journalists and access logs of their home and cellular phone calls.

The probe resulted in the resignation of two HP directors and the demotion of a third. George Keyworth II quit the board after acknowledging he was a source of the leaks, while Thomas Perkins stormed out of a May 18 board meeting in protest of the investigators' tactics. Dunn will step down as chairwoman in January and be replaced by HP CEO Mark Hurd.

As HP's staff attorney, Baskins allegedly oversaw the leaks investigation and declared it to be legal.

HP insiders and contractors are likely to invoke their Fifth Amendment right against self-incrimination rather than testify before Congress and possibly expose themselves to criminal charges, one legal expert said.

"Though the appearance will be gruesome ... to do otherwise might not be prudent," said Ed Harmon, a partner with Thorp Reed & Armstrong in Pittsburgh, Pa.

Meanwhile, the lawsuit was filed Thursday in Santa Clara County Superior Court by Juliet Worsham, on behalf of all HP shareholders. It alleges "substantial expense and damage" to the company from the investigators' use of pretexting and seeks to have Dunn, Baskins, Hurd, DeLia and several members of the HP board found to have breached their fiduciary duties and abused their power.

It asks for the defendants to reimburse HP for any financial damage suffered by shareholders as a result of the pretexting scandal and to "reform and improve its corporate governance and internal control procedures."

The suit also says the company is incapable of protecting itself from the various charges that are likely to result from the scandal because its top legal advisers are also possible subjects of prosecution.

"Therefore this derivative action must be brought and vigorously prosecuted to protect and vindicate the rights of HP," the lawsuit reads.

HP's Moeller declined to comment on the lawsuit.

Contributing: Brian Bergstein