O’SMACH, Cambodia (AP) — In the town of O’Smach, along Cambodia’s northern border with Thailand, stands a compound of abandoned buildings that were battered by shelling during recent weeks of armed clashes.

The site, now occupied by Thai troops, had served as one of Cambodia’s notorious scam centers, according to Thai officials.

A six-story building, shown to journalists and international observers on Monday during a trip organized by the Thai military, is scattered with documents, equipment and personal belongings, likely abandoned in haste.

“They are well-organized. They have good infrastructure and systems, and also the workflow and many, many tactics and techniques to do the scams,” said Lt. Gen. Teeranan Nandhakwang, director of the Thai army’s intelligence unit.

Experts say such scam operations in Cambodia and elsewhere have cheated people around the world out of billions of dollars and tricked people from many countries to work in them under slave-like conditions.

The Thai military said the compound was secured during the December clashes because Cambodian forces had used it as a military base.

A ceasefire reached in December stipulated that the warring sides would de-escalate tensions and hold their forces at the positions they occupied prior to the agreement. That includes the compound on Cambodian soil now occupied by Thai troops.

Dozens of rooms have wooden booths lined with foam for soundproofing, scripts written in multiple languages, lists of names and phone numbers, computer monitors and empty brackets for hard drives.

There are also mock-up sets resembling police stations and uniforms of law enforcement of at least seven countries: China, Australia, India, Indonesia, Vietnam, Singapore and Brazil.

One room has a replica of what appears to be a Vietnamese bank branch, complete with service counters, banners and a waiting area.

The set-ups served as essential to a scam where people are targeted by scam operators pretending to be officials or other authority figures. Scripted approaches were meant to threaten arrest or other legal action unless instructions were followed.