A private investigator hired to get to the bottom of boardroom leaks at the Hewlett-Packard Co. (HPQ) got tips from a former news reporter about how to dupe a journalist into revealing the source of a damaging story about the company.

Details of the plan were revealed in congressional documents provided Monday to the Associated Press and other news outlets. A congressional panel is investigating HP's possibly criminal probe, which has prompted the departure of three board members and three top employees.

The target of the sting was Dawn Kawamoto of CNET's News.com, who wrote a story based on an anonymous source that described a private board retreat at a posh resort and prompted HP to renew a previously unsuccessful probe into boardroom leaks. Her source was later identified as then-board member George Keyworth II.

In an e-mail dated Feb. 6, Ronald DeLia of Security Outsourcing Solutions wrote to the HP team spearheading the probe that a former reporter named "Diane" suggested to him several strategies for tricking Kawamoto.

One recommended tactic to build trust was to send Kawamoto a tip with a piece of unannounced news about the computer and printer maker that was about to be make public.

The investigators, who were planning to plant tracking software on the e-mail attachment to identify anyone it was forwarded to, were instructed to send the document at least two days before it was made public instead of just one, because "information obtained 2 days prior to its release has more of an 'insider feel,'" DeLia wrote.

"The reporter has to feel comfortable or have a sense the source is someone who has accurate information and is in a position to know," he wrote.

Also, HP investigators apparently coordinated with the company's media relations department to bait that e-mail with a juicy bit of unannounced real news in an attempt to "gain some major credibility" with Kawamoto, according to an e-mail from HP's then-ethics chief Kevin Hunsaker.

The investigators tried to lure the reporter with a piece of upcoming news concerning the appointment of a new leader for HP's handheld business unit, a plan that was cleared by then-Chairwoman Patricia Dunn, then-General Counsel Ann Baskins and Chief Executive Mark Hurd.

In e-mails between HP security team members on Feb. 8 and 9, the investigators detail plans for Bob Sherbin, HP's head of public relations, to send the news release to Hunsaker at least two days before the public announcement.

The security squad would then install the tracer technology and send the message to Kawamoto.

Reached late Monday, Sherbin said he didn't know about the tracer technology and believed the news release would be used properly.

"I was acting under instruction from senior management, and I had every reason to believe that the material would be used properly," Sherbin said.

But the investigators first needed approval from Dunn and Hurd, which came in a Feb. 9 e-mail from Dunn to Hunsaker and Baskins: "I spoke with Mark and he is on board with the plan to use the info on new handheld leader," Dunn wrote.

Hurd later testified that he approved the plan but said he didn't recall authorizing the use of the tracer technology, which is not generally considered illegal.

The rigged e-mail was sent later that day, and one member of the security detail, Anthony Gentilucci had trouble containing his excitement.

"This is like waiting for the Apollo 13 spacecraft to emerge from the dark side of the moon," said Gentilucci, who has since resigned from HP.

The company said later that the tracer trick was unsuccessful, possibly because the software failed or Kawamoto didn't open the attachment.

Four days later, on Feb. 13, HP officially announced the news contained in the message that it was making its handheld business a separate unit within its Personal Systems Group division, and that former Sun Microsystems (SUNW) executive Dave Rothschild would lead the unit.

In other revelations from the congressional documents, an HP security expert instructed an investigator to make "make absolutely sure" he deleted private phone records of non-HP employees obtained in the company's ill-fated effort to root out the source of boardroom leaks.

Fred Adler, a former FBI agent working in HP's IT security investigations department, vowed in the Feb. 9 e-mail to investigator Arthur Molineaux that he would also delete records that were not the property of the company, according to the documents.

"As for the non-HP owned records you obtained and sent to me in an unsolicited, good faith attempt, please make absolutely sure you delete them as you stated you would," wrote Adler, who has been praised with another member of the security detail for sounding the alarms that HP's tactics might land it in legal trouble. "I will do the same."

An HP spokesman reached late Monday night declined to comment on the e-mail.

To unmask the person who leaked private boardroom discussions to the media, HP investigators and third-party detectives combed through detailed phone logs of directors, journalists and former and current HP employees, and rummaged through trash, trailed targets when they went out of town.

Federal and state authorities are investigating whether HP insiders or contractors violated the law by obtaining the phone records through a shady practice known as "pretexting," in which the investigators impersonated their targets to trick the phone companies into coughing up private records.