David de Sola | Washington, DC | March 27

CNN - Two teams of government investigators using fake documents were able to enter the United States with enough radioactive sources to make two dirty bombs, according to a federal report made available Monday.

The investigators purchased a "small quantity" of radioactive materials from a commercial source while posing as employees of a fictitious company and brought the materials into the United States through checkpoints on the northern and southern borders, according to a Government Accountability Office report prepared for Senate Permanent Subcommittee on Investigations Chairman Norm Coleman, a Minnesota Republican.