HP has turned over thousands of documents to a US House subcommittee investigating methods the company used to find out who was leaking company information to the media, a subcommittee spokesman said yesterday.

"The committee did receive thousands of pages of documents from HP. Staff investigators are reviewing them now," said Terry Lane of the Subcommittee on Oversight and Investigations of the House Committee on Energy and Commerce.

HP confirmed it responded to the subcommittee's request but didn't go beyond that. "We are complying with the House Subcommittee's request for information but are not releasing the details of what's being provided for the committee's inquiry," said HP spokesman Ryan Donovan.

The inquiry springs from revelations that HP hired an outside investigative firm that used questionable tactics to find the source of leaks from the HP board to news media in 2005 and 2006. HP, in a US Securities and Exchange Commission (SEC) filing 6 September, acknowledged that unnamed outside investigators used 'pretexting', a form of subterfuge where investigators pose as someone else, to obtain personal phone records of people it was investigating. The committee is considering federal legislation to make pretexting illegal.

The House panel, in a 11 September letter to HP Board Chairman Patricia Dunn, asked HP to: identify the outside investigative firms it hired; identify the people within HP who authorised, participated in or had knowledge of HP's investigation; provide copies of contracts between HP and any outside firms; disclose the identities of everyone whose phone records were procured, or were attempted to be procured; and provide other information.

HP has refused to identify the outside firms it hired, but various media reports have identified them as Security Outsourcing Services and Action Research Group.

Although HP has claimed that its legal advisors told it that the pretexting was within the law, an HP security specialist reportedly questioned its legality earlier this year.

Fred Adler, a computer-crimes specialist within HP's global security division, and a former FBI agent, notified his supervisors that acquiring people's phone records under false pretenses could be against the law, The Wall Street Journal reported today.