Bill Ries-Knight used eBay's auction site to purchase what he thought was a brand-new PC hard drive.
When it arrived at his home, however, the Californian resident found a used drive that contained proprietary data of the Democratic Party of Arkansas - including the mobile phone numbers of Democrats in the state's congressional delegation.
None of the information was encrypted, said Ries-Knight, and only a fraction was password-protected.
In a telephone interview, Ries-Knight, a computer technician, said that although he didn't look at all the files, he did find the private mobile phone numbers of Senators Blanche Lincoln and Mark Pryor, and Representatives Marion Berry, Mike Ross and Vic Snyder.
Ries-Knight said the drive came from an apparently damaged computer once owned by Bruce Sinclair, state director of the Arkansas Democratic Party.
He also said that the drive had been listed on eBay by the wife of David Qualls, a friend of a state Democratic Party official and a lead programmer/analyst for the Arkansas state government. Qualls told Ries-Knight that his wife thought the drive was new.
Sinclair and Qualls declined to comment.
"Cases like this probably happen more than we hear about, but I think it's sporadic," said Pete Lindstrom, an analyst at Burton Group in Midvale, Utah.