The FBI has recently adopted a novel investigative technique: posting hyperlinks that purport to be illegal videos of minors having sex, and then raiding the homes of anyone willing to click on them.

Undercover FBI agents used this hyperlink-enticement technique, which directed Internet users to a clandestine government server, to stage armed raids of homes in Pennsylvania, New York, and Nevada last year. The supposed video files actually were gibberish and contained no illegal images.

A CNET News.com review of legal documents shows that courts have approved of this technique, even though it raises questions about entrapment, the problems of identifying who's using an open wireless connection--and whether anyone who clicks on a FBI link that contains no child pornography should be automatically subject to a dawn raid by federal police.

Roderick Vosburgh, a doctoral student at Temple University who also taught history at La Salle University, was raided at home in February 2007 after he allegedly clicked on the FBI's hyperlink. Federal agents knocked on the door around 7 a.m., falsely claiming they wanted to talk to Vosburgh about his car. Once he opened the door, they threw him to the ground outside his house and handcuffed him.

There's no evidence the referring site was recorded as well, meaning the FBI couldn't tell if the visitor found the links through Ranchi or another source such as an e-mail message.