LAST January an online account was set up with the phone company AT&T for Tom Perkins. His social security number and a home phone number were used to verify it was Perkins, a former Hewlett-Packard board member, setting up the account. Except it wasn’t.

He had become a victim of “pretexting” — a scam where crooks use bits of personal information as a jemmy to force their way into deposits of more valuable information. A technique usually used by credit-card fraudsters, in this case the pretexters’ ultimate paymaster was one of the world’s largest technology companies.

The fraudulent account was used to monitor Perkins’s phone calls by a private investigation firm in the pay of his former employer, HP.

Perkins wasn’t the only one having his calls monitored. Other directors’ calls were sought and attempts were also made to get the phone records of nine journalists as HP tried to find who was leaking information about the company’s hardening attitude towards Carly Fiorina, its now former chief executive.

Obtaining information by impersonating someone else is illegal in California, where HP is based, and the state attorney-general’s office has said it believes crimes were committed in connection with the probe.

HP has stressed it did not know pretexting was being used by the companies it employed to conduct the investigation. But its hand-washing argument may not be enough to save Patricia Dunn, the non-executive chairman.

Dunn revealed the findings of her probe to the HP board in May. George Keyworth, former science adviser to President Ronald Reagan, was implicated as the source of many of the leaks. A row ensued and Perkins, a friend of Keyworth, resigned.

Perkins is also a director of News Corp, ultimate owner of The Sunday Times. According to The Wall Street Journal, he was told by another News Corp director, Viet Dinh, a former US assistant attorney-general, that the phone search was illegal and “unconscionable”.

The Securities and Exchange Commission is now looking into the case and the pressure is mounting on Dunn.

So far, HP has argued it did not know the phone records had been illegally retrieved. “The situation is regrettable,” said Dunn in a statement. “But the bottom line is that the board has asserted its commitment to upholding the standards of confidentiality that are critical to its functioning. A board can’t serve effectively if there isn’t complete trust that what gets discussed stays in the room.”

But Dunn has only to look over the Hollywood hills if she wants to see how much trouble she is in. The authorities in Los Angeles are pursuing their case against Anthony Pellicano, a self-styled “private investigator to the stars”.

He is charged with illegal wiretapping and fraud, charges he denies.

The case has been highly embarrassing for his former clients, including the prominent Hollywood lawyer Bert Fields and executives such as former agent Michael Ovitz. Half a dozen people have so far been charged in the case including Terry Christensen, one of Hollywood’s top lawyers.

HP has had a dysfunctional history over the past few years. Fiorina was a divisive figure, famously clashing with Walter Hewlett, the son of co-founder Bill Hewlett. No doubt Dunn was trying to get the company back on a more even keel when she launched this probe. But has she demonstrated a colossal error of judgment? At best the information obtained was dubious, at worst it was illegal.

If Dunn truly cared about asserting her “commitment to upholding standards of confidentiality”, surely she would have applied those standards to her directors. It appears the ends do not justify the means.