A Congressional committee has ordered Hewlett Packard (HP) to hand over records related to its internal inquiry into boardroom leaks.
Reports suggests Ms Dunn is in a precarious position
The request came as HP planned to meet once more to discuss the fate of its chairwoman Patricia Dunn.
Earlier, the computer and printer maker confirmed federal prosecutors had asked for information about the probe.
California and US authorities have been investigating whether any laws were broken during the investigation.
Reports suggest the talks could lead to chairwoman Patricia Dunn being ousted. She has stood by her decision to hire undercover consultants for the probe.
The US House Energy and Commerce Committee is the latest organisation to wade into the so-called "spying scandal" at the firm.
In a filing to the Securities and Exchange Commission, the computer and printer maker added it was "co-operating fully" with the federal inquiry, as well as one being carried out by the California State Attorney General's Office.
In a bid to discover which employee had leaked "confidential" reports to the press, investigators obtained the phone records and other data of journalists and HP employees without their permission.
The practice - known as "pre-texting" - is a common one among private investigators but tests the limits of California state laws as prosecutors believe it violates laws covering identity theft and unauthorised access to computer data.
Last week, Ms Dunn said she had no idea of the tactics private investigators would resort to, adding she was "appalled" journalists had been targeted.
"This was not my spy campaign on our board," she said, adding she was willing to step down from her post if called to do so.
Board member George Keyworth was identified as the source of the leak.
Mr Keyworth stated that he had leaked information but refused to step down, despite being asked to.
As a penalty, HP barred him from seeking re-election to the board.
But Ms Dunn's methods sparked strong protests from board member Thomas Perkins.
Mr Perkins, a Silicon Valley venture capitalist, has since resigned his seat in protest at the use of pretexting and demanded Ms Dunn resign.
The firm's investigation of staff members came to light in a Securities and Exchange Commission (SEC) filing, in which HP acknowledged using an outside company to look into the leaks.
HP started to investigate workers after "multiple leaks of confidential HP information, including the internal deliberations of its board of directors," from 2005.