HP chair, Patricia Dunn, will answer questions on the spying scandal that has embroiled her company during a House committee hearing on Capitol Hill next week.

HP general counsel, Ann Baskins, will also appear at the hearing of the Subcommittee on Oversight and Investigations of the House Committee on Energy and Commerce, according to company spokesperson, Ryan Donovan.

HP's lead outside counsel, Larry Sonsini of Wilson, Sonsini, Goodrich & Rosati, will also testify, according to committee spokesperson, Terry Lane.

Sonsini advised HP on the legality of its investigation into media leaks of details from the company's board meetings between 2005 and 2006.

Earlier this month, HP revealed it had hired outside investigators to find the source of those leaks and that they had impersonated the subjects of their investigation in order to gain access to private telephone records. In the course of the search, HP board members and reporters were impersonated.

The committee is looking into HP's methods and is considering new federal legislation that would make this 'pretexting' illegal.

HP is also being investigated by the Attorneys General of California and Massachusetts, the US Federal Bureau of Investigation and the US Attorney's office.

Ronald DeLia of investigation firm Security Outsourcing Solutions is also set to appear, but Lane said it is possible he will invoke his Fifth Amendment right to not testify to protect against self-incrimination. Prosecutors are reportedly looking into DeLia's company and a Melbourne, Florida, investigation company, Action Research Group, in connection with the scandal.

In a June 11 Congressional hearing on pretexting, several investigators invoked their Fifth Amendment rights and refused to answer questions on the practice, which is considered to be in a legal grey area.

The committee has also asked HP global security manager, Anthony Gentilucci, and Action Research Group owner, Joe Depante, to testify, but has not heard back from them, Lane said.

HP has already provided the committee with "thousands of pages of documents" in connection with its investigation, Lane said.

The pretexting scandal has been front-page news for several weeks now and has forced Dunn to step down from her role, effective January. But it has not had much of an effect on the company's financial performance. HP's (HPQ) stock has hovered in the $US36 range since news of the affair first broke three weeks ago.