With huge numbers of visitors and patchy law enforcement, Thailand has a booming black market for fake identity documents, and it was here that two passengers on a missing Malaysia Airlines jet were apparently able to get hold of stolen passports.
Thai authorities struggle to track thousands of lost or stolen passports each year. Some are known to be sold on through syndicates to drug traffickers. Others are suspected to have ended up in the hands of Islamist militants.
"Fake passports and identity fraud in general is a massive problem in Thailand," police commander and Thailand's Interpol director Apichart Suriboonya told Reuters.
Sometimes documents are sold by their owners to cover travel costs, Apichart said.
They are passed on to middlemen, Thai or foreign, who work with criminal networks, he said. The passports may be altered, for example with a new photograph, but sometimes the fraudulent user hopes to pass as the real owner.
The passenger manifest issued by Malaysia Airlines included the names of two Europeans - Austrian Christian Kozel and Italian Luigi Maraldi - who were not on the plane. Both had passports stolen on the Thai holiday island of Phuket.
The passports were used to buy tickets from travel agents in the resort town of Pattaya, to Beijing and on to Europe. Thai and foreign investigators were questioning staff at one travel agent on Monday.
There is no evidence the plane's disappearance is linked to the two passengers travelling under the stolen passports.
Police showed Reuters a copy of Maraldi's passport used to make the travel booking with what was apparently the original photograph of Maraldi in it. It was not immediately clear if the tickets were bought online or collected.
Thailand's fake document business has been flourishing for years.
In 2010, Thai and Spanish authorities arrested suspected members of an international ring providing forged passports to militants. Thai authorities say the ring may have passed fake documents to those behind the Madrid train bombings in 2004.
Pockets of Bangkok are notorious counterfeit goods emporiums with fake drivers' licences, press cards and airline cabin crew identity cards on display. The Thai capital also boasts experts in forging visas.
"Thailand is fertile territory for people looking to steal European passports, there are lots of foreigners and many foreigners visit," a European diplomat said.
The Ministry of Foreign Affairs said more than 60,000 passports - both Thai and foreign - were reported missing or stolen in Thailand between January 2012