http://www.cbsnews.com/stories/2011/10/14/earlyshow/main20120395.shtml

CBS News investigative correspondent Sharyl Attkisson, who has reported on this story from the beginning, said on "The Early Show" that the investigation into the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF)'s so-called "Fast and Furious" operation branches out to a case involving grenades. Sources tell her a suspect was left to traffic and manufacture them for Mexican drug cartels.

Police say Jean Baptiste Kingery, a U.S. citizen, was a veritable grenade machine. He's accused of smuggling parts for as many as 2,000 grenades into Mexico for killer drug cartels -- sometimes under the direct watch of U.S. law enforcement.

Law enforcement sources say Kingery could have been prosecuted in the U.S. twice for violating export control laws, but that, each time, prosecutors in Arizona refused to make a case.

Grenades are weapons-of-choice for the cartels. An attack on Aug. 25 in a Monterrey, Mexico casino killed 53 people.

Sources tell CBS News that, in January 2010, ATF had Kingery under surveillance after he bought about 50 grenade bodies and headed to Mexico. But they say prosecutors wouldn't agree to make a case. So, as ATF agents looked on, Kingery and the grenade parts crossed the border -- and simply disappeared.