The woman in Grand Horizon, a travel agency in Phuket, raised her hand and said "No, no, no" as I walked in. But by then I was already inside.
"You have to understand, it is not our fault," she said repeatedly, her eyes darting nervously to the glass doors. She wore a hijab, carefully torn jeans and hazel-coloured contact lenses. She refused to give her name. Another woman sitting at the counter, also in a hijab and coloured contact lenses, did not move, but just looked resigned and smiled at me.
Several police agencies in Pattaya have been sifting through the facts and the speculation to piece together the trail that began when an Austrian and an Italian had their passports stolen in Phuket. The thefts occurred over the last two years.
The use of the stolen passports to buy tickets on the ill-fated MH370 - for two Iranian men, including a 19-year-old who was flying to Frankfurt where his mother was waiting for him - has shone a harsh light on Thailand as a hub for stolen, fake and altered passports, and an illegal migration route.
It has been a laborious investigation, hampered by a blizzard of rumour and speculation. What is known now is that an Iranian national, Ali Reza Hashem, who apparently once owned a restaurant in Pattaya and now lives in his native Iran, made the original flight reservations for the two, who were routed to fly from Kuala Lumpur to Beijing and on to Europe.
Ali Reza Hashem still has friends and connections in Pattaya. Reports citing official records say he last entered Thailand on June 11, 2013, and left on Dec 1 that year - just three months ago.
Once the reservations were made online, on China Southern airlines which had a code share with MH370, a friend of Mr Ali in Pattaya, identified in reports as Mr Hashem Saheb Gharani Golestani, also an Iranian, apparently paid for the two tickets from Grand Horizon.
Grand Horizon is not accredited by the International Air Transport Association (IATA) and thus did not issue the tickets. Instead it asked an accredited travel agency, Six Stars, to issue them. This is quite routine for non-accredited agencies.
Neither of the agencies saw anything amiss when they saw the photocopies of the two passengers' passports.
The woman in Grand Horizon said Mr Ali was well known to the agency, but insisted she had never seen him herself. He often e-mailed ticket requests, she said, as she saw me out and locked the door behind me, shutting out another journalist trying to get in.
The agency is in a Middle Eastern quarter of Pattaya, a city of less than half a million people, but swollen by between 7 and 9 million tourists annually. Egyptian and Moroccan sheesha restaurants, Arabic boutiques, Indian restaurants are cheek by jowl with tour agencies and massage parlours.
Pattaya's crammed beaches and its central police station reflect the international traffic in this city - and what can go wrong. Volunteer police officers from other countries are part of the staff at the police station. A few kilometers away at the immigration office, a Turkish man who speaks three languages helps officers at the Transnational Crime Data Centre communicate with foreigners.
Police have been to see Mr Golestani in Pattaya, and through him have tried to contact Mr Ali, who has not responded, says Pattaya police chief Colonel Supachai Puikaekham.
The authorities in Thailand, Malaysia and at Interpol have concluded that while terrorism cannot be entirely ruled out, the evidence thus far on the stolen passport issue points to illegal migration.
Still, the episode has lifted the lid on the "underground railroad" - a term once used to describe the slave trade and persisting now to describe modern illegal migration.
In many cases, tourists who need money even sell their passports and then report them as stolen. Thailand does not have its own database of lost and stolen passports, but is now mulling setting one up.
It has been a wake-up call and drawn unwanted international attention - something Thai authorities are always wary of.