E-mail Address on Porn Listserv Led Police to Minnesota Professor.

Byline: Leslie Brooks Suzukamo

Jul. 29--For months, it was as if he were invisible.

Richard Pervo, a professor at the University of Minnesota, freely used his e-mail at work to download thousands of images of child pornography, and his digital contraband slipped unnoticed into the torrent of data that roars daily through the school's massive Internet connections.

But Pervo left one stray thread dangling: his university e-mail address.

Investigators at the university and the Minnesota Internet Crimes Against Children Task Force grabbed hold and followed it to the Department of Classical and Near East Studies and through the frosted glass door of Pervo's one-man office. There they found scores of shiny CDs containing child pornography scattered among CDs filled with Christian scholarship and digital Bibles. The hard drive of his school-issued desktop computer brimmed with more child-porn files, along with Pervo's work.

Later, Pervo would tell police, "I was stupid, but this is good. It'll stop me from doing it."

Sgt. Brook Schaub, the task force's computer-evidence recovery expert who helped the university put together a search warrant for Pervo's computer, would muse: "You almost got the feeling that …