Rohingya migrants slipping into the country are a common sight, but most witnesses are afraid to report what they see to the authorities, locals in the border district of Sadao said.
People renting rooms in the area said they saw the migrants being brought to a deserted warehouse on Soi Thai-Jungloan 3, a stone's throw from the border with Malaysia.
More than 300 Rohingya migrants were found hiding earlier this month in the same warehouse. They are now in the custody of the authorities.
When night fell and tourists from Malaysia began crossing into Sadao to indulge in some nightlife entertainment, the illegal migrants would scurry out from their hideouts and sneak into Malaysia through large holes they cut in the mesh fence on the border.
"This happened all the time. We saw them bring the migrants to the warehouse. But no one reported it. The masterminds are big and powerful. I'm scared of them," said a 60-year-old female dressmaker who asked not to be named.
A 35-year-old staff member of a nightclub who lives barely 10 metres from the warehouse said the depository was a transit point for illegal migrants heading into Malaysia.
After one group of migrants leaves, new faces arrive a few days later, said the man, who called himself Aod.
He said he had told his colleagues at the club about the warehouse refuge but no one took any interest.
He mustered up the courage to report the storehouse to the police but no one came to inspect the place, Aod said.
Seeing migrants coming in and out of the warehouse became a routine sight, the club worker said.
People in the neighbourhood went about their daily lives and minded their own business.
With many tourists visiting the district, having strangers around was not disturbing for the locals, Aod said.
A 62-year-old female Muslim food vendor who lives in a rented house nearby said she had known for a long time that the warehouse was used to hold illegal migrants before they are smuggled into Malaysia.
She said she usually comes home from selling food at 2am to 3am every day.
At this time she usually saw migrants being herded into the warehouse.
Surasak Hudsamud, a border patrol police officer, said a number of buildings in the area were built illegally as they were too close to the borderline.