NEW YORK (CNNMoney.com) -- The House Energy and Commerce Committee released prepared testimony from former Hewlett-Packard chairman Patricia Dunn and chief executive Mark Hurd Wednesday ahead of a hearing on the company's controversial spying program.

Dunn and Hurd both expressed regret over the methods used to find the source of a company leak in their prepared remarks, but they also distanced themselves from having knowledge of the "pretexting" tactics used in the investigation.

Lawmakers will seek more details of their involvement in the boardroom probe Thursday during a question and answer session before the panel.

In her prepared testimony, Dunn said she became aware that phone records were obtained during the probe in the spring of 2005 but that she believed these records were accessed legally.

HP has been grappling with a privacy scandal since it disclosed early this month that its investigators used pretexting - a potentially illegal practice that involves using false pretenses to obtain personal information - in order to access phone records of board directors, employees and journalists.

Dunn also said she was under the impression that HP chief financial officer Bob Wayman had authorized the leak probe and that at no point did she consider herself the investigation's "supervisor."

HP said Wayman wasn't involved in the probe. "To the best of our knowledge, Bob Wayman had no involvement whatsoever in the leak investigation. Any assumption about Bob Wayman's involvements made by Ms. Dunn was nothing more than that, an assumption," spokesman Ryan Donovan said.

Dunn has taken the brunt of the criticism surrounding the leak investigation - last week she resigned as chairman and director at the request of the board. But she defended the need to find the source of the leaks in her testimony, describing it as "unfinished business" in the wake of ousted chief executive Carly Fiorina's departure in February 2005.

Hurd, in his prepared remarks, said the use of potentially illegal tactics occurred because of a breakdown in internal controls and that the investigation team became so focused on finding the leaker they lost sight of the company's values.

Hurd, who has come under fire for not doing enough in the wake of the spying scandal, said he wishes he had asked more questions but that he is focusing on how the company addresses its mistakes.

His remarks echoed those he made at a press briefing on Friday, when he acknowledged he was aware of some questionable tactics.

In addition to hearing from Dunn and Hurd, the House Energy and Commerce Committee will hear from HP general counsel Ann Baskins on Thursday. A string of others involved in the case also have been requested to appear at the hearing.

Earlier Wednesday the House panel said it had subpoenaed five private investigators to testify at the hearing. Ronald DeLia, one of the private investigators who worked on the probe, also has been subpoenaed.

Pretexting is at the center of an investigation that has been building in Congress for months. State and federal authorities have also been investigating the practice.

California Attorney General Bill Lockyer has said crimes were committed at HP and that he has enough evidence to indict HP officials and outside contractors.

The HP scandal has rocked the Silicon Valley heavyweight's board. George Keyworth, who was fingered as the source of the leaks, and his friend Thomas Perkins both quit the board in protest of the company's surveillance tactics.

But shares of HP (Charts), which have outperformed rivals Dell (Charts) and IBM (Charts) in the last year, have held up fairly well. Shares have dipped about 3 percent in the three weeks since the scandal broke.

HP lights the privacy powder keg