Although the dangerous radioactive cargo has been recovered, authorities say the two thieves who stole a truck carrying cobalt-60 in Mexico on Monday "will, without a doubt, die," because they removed the material's protective casing. Mexican nuclear safety official Mardonio Jimenez said the culprits will "have severe problems with radiation," even though they were likely only exposed for a brief time.

An international warning went out from the U.N.'s nuclear watchdog after the truck went missing, since cobalt-60 can be used to make an improvised nuclear weapon, or a "dirty bomb." IAEA Director General Yukiya Amano said last year that such a bomb could, if detonated in a major city,  "cause mass panic, as well as serious economic and environmental consequences." Cobalt-60 is used in radiotherapy machines and was being transported from a Tijuana hospital to a nuclear waste facility when it was unwittingly intercepted by the carjackers.

CNN reports that authorities believe all of the material was found on Wednesday, roughly 25 miles away from the recovered truck, and that it could take weeks to clean the area. 

If you're thinking that it shouldn't be this easy to steal radioactive material, you're right. Mexican authorities say the truck wasn't properly prepared to carry the Cobalt: 

"At the time the truck was stolen, the source was properly shielded," the IAEA said. "However, the source could be extremely dangerous to a person if removed from the shielding, or if it was damaged." But [head of Mexico's National Commission for Nuclear Security and Safeguards Juan Eibenschutz Hartman] said the truck wasn't properly set up to transport the radioactive material, since it didn't have a GPS for tracking or other necessary equipment.

Authorities have yet to track down the criminals, but believe they will soon appear at a radiation treatment clinic.