Updated from 5:00 p.m. EDT

Congress picked up the mantle of sorting through who knew what -- and when -- at

Hewlett-Packard

(HPQ) - Get Report

, as CEO Mark Hurd and several membersof the Palo Alto, Calif., tech giant appeared before ahearing regarding its controversial efforts to investigate media leaks.

But while seven hours of interrogation by legislatorsteased out more details about the affair, crucialquestions regarding who approved the plan to accessthe personal phone records of board members, employeesand journalists -- and why no one in the company's topranks questioned the methods used to gather the data --remained unanswered.

CEO Mark Hurd described a breakdown in H-P'sinternal processes, including his own failure to reada report addressed to him and others that detailedsome of the controversial methods used in theinvestigation.

Overall however, Hurd described his involvement in theinvestigation as arm's length, at best.

"In terms of the priorities of H-P at that point intime, this was not the CEO's No. 1 priority,"Hurd said.

Hurd and former Chairwoman Patricia Dunn disavowed anyknowledge that pretexting -- falsely impersonatingsomeone to gain access to their personal information -- was part of the investigation until well after the conduct had occurred.

Both said it wasn't until June 2006, when formerboard member Thomas Perkins began to raise concernsabout some of the methods used in the internalinvestigation, that they became aware of the practice. Dunn said she didn't learn that journalists also werebeing pretexted as part of the investigation untilearlier this month.

Indeed, Dunn, who resigned amid the scandal last week,told members of the House Energy and CommerceCommittee that she believed any personal phone recordsobtained by H-P were from publicly available sources. "I understand why that might seem strange today,knowing what I know now," said Dunn.

Dunn's testimony Thursday followed the appearanceearlier in the morning of 10 individuals involved inthe H-P leak investigation, ranging from privateinvestigators to H-P General Counsel Ann Baskins, whoresigned this morning. All 10 individuals declined toanswer questions, invoking their Fifth Amendmentright, to the consternation of some House members.

The committee is conducting a broad inquiry intopretexting.

H-P has acknowledged that its efforts to plugboardroom media leaks may have led privateinvestigators it hired to access personal phonerecords of board members and journalists throughpretexting.

In a hearing marked by grandstanding as much as byfact-finding, legislators took turns grilling thevarious witnesses and expressing indignation at thewhole affair. Michigan Rep. John Dingelldescribed H-P's leak investigation as "aplumber's operation that would make Richard Nixonblush if he were alive."

Drawing from a thick binder of documents collectedfrom H-P, legislators pointed to several items thatappeared to indicate that key personnel within thecompany were aware that pretexting was a part of theinvestigation from early on.

Legislators cited handwritten notes by Baskins, whichspecifically mention using pretexting to extractinformation from telephone companies. The initials ofPatricia Dunn appear in the same document with certainquestions.

Dunn said she did not recall participating in themeeting represented by the notes, nor, she said, didshe recall a 2005 conversation in which one of theprivate investigators claims to have explained themethodology of pretexting to her.

Following her appearance, Dunn's attorney released astatement disputing the description of certain aspectsof the investigation's timeline and allegationsabout her involvement in meetings recently made publicby H-P.

Appearing alongside Dunn at the hearing were FredAdler, an H-P employee in charge of securityinvestigations, and Larry Sonsini, the prominentSilicon Valley attorney who serves as H-P's mainoutside counsel.

In one email that Sonsini sent to a former H-P boardmember, the attorney says it appears that the methodsused by H-P in the leak investigation werepermissible. When pressed by legislators about thesestatements, Sonsini repeatedly stressed that he wasmerely conveying the information he received fromH-P's in-house legal department in his email, ratherthan passing his own legal opinion on pretexting.

"I was not an expert in these matters. I did no knowwhat pretexting meant at that time. I was not asked toinvestigate it at that time," Sonsini said.

In fact, a picture emerged throughout the hearingsuggesting that over the course of H-P's investigationthe company may have relied on only a single legalopinion about pretexting. That opinion, it appears,was authored by a clerk at the law firm used by one ofthe private investigators.

H-P shares closed Thursday up 1.6% to $35.97.