Mexican officials say they have recovered a heap of stolen radioactive material, but said the thieves must have exposed themselves to life-threatening radiation levels.
The theft of cobalt-60, which is used in hospital radiotherapy machine, had set off an international scare as it was feared the material could be used for making a dirty nuclear bomb.
At the end of a massive two-day search operation, it was discovered abandoned near the town of Hueypoxtla, Mexican officials said.
The material was being transported in a specially equipped Volkswagen truck from a hospital in the border town of Tijuana to a storage centre in central Mexico when thieves hijacked the truck and set off with the material, apparently unaware of the nature of the cargo.
"We found the radioactive source removed from its container and left between 500 and 700 metres," said Mardonio Jimenez, an official at Mexico's National Nuclear Security Commission (NNSC).
Mexico had alerted the International Atomic Energy Agency (IAEA) about the theft.
"At the time the truck was stolen, the source was properly shielded. However, the source could be extremely dangerous to a person if removed from the shielding, or if it was damaged," the IAEA had said.
The thieves had hijacked the truck as the drivers made an overnight rest stop at a petrol station in the town of Tepojaco, according to the BBC. They tied up the driver at gunpoint and left with the vehicle.
The theft of the radioactive material had triggered international alarm bells, but it was later concluded that the robbery was one of those that regularly take place in the area targeting expensive cargo trucks.
"The vehicles are expensive because of the mechanisms to load and unload heavy material. That type of theft is very common in that area. That's why we feel the people who did this have no idea what they stole," Jimenez said.
He said the NNSC believed the thieves did not know what they had and they "were interested in the crane, in the vehicle".
"The people who handled it will have severe problems with radiation ... They will, without a doubt, die," he said, according to the Washington Post.