Some US experts worry that a smuggling ring gave rogue states plans for a light warhead, apparently from Pakistan.
An infamous atomic smuggler may have had blueprints for a compact, sophisticated nuclear warhead, and that could mean that the world's proliferation problem is even worse than many experts had thought.
US officials have long declared the nuclear technology ring run by Pakistani scientist Abdul Qadeer Khan to be shattered. But revelations that a digitized bomb design turned up on the computer of an associate of Mr. Khan's show that US and UN investigators may not yet know everything Khan did, despite the fact that he has been under house arrest in Pakistan for years.
At the least, the US should now press Pakistan for direct access to Khan, says one expert. Secondhand intelligence reports may no longer be good enough.
"People seem to have taken the Bush administration line that we have rolled up A.Q. Khan's network. I don't believe it," says Jon Wolfsthal, a senior fellow in the international security program at the Center for Strategic and International Studies (CSIS) in Washington.
The design in question is for a relatively small and light warhead, apparently of Pakistani origin. Computer files containing the design were among the items seized by Swiss authorities from Swiss nationals Freidrich, Marco, and Urs Tinner in 2004, according to a report by David Albright, a former International Atomic Energy Agency (IAEA) inspector, made public on June 16.
The computer files were encrypted and difficult to decipher, according to Mr. Albright. At least one current IAEA official doubts that the Tinners, former associates of Khan's, were the only people in possession of the design.