The arrests followed the execution of a search warrant at a warehouse operated under the name of Natcha Nophokiew on the southern resort island on Thursday, reports the Bangkok Post.
Officers found goods believed to have been stolen from Chaweng Blue Lagoon The Teak Wing Hotel in Tambon Bo Phut, said Bo Phut Police Chief Yuthana Sirisombat.
Police now have nine suspects in custody, including three workers from Myanmar.
Col Yuthana said Ms Natcha, 31, and Chaisak Chanchaem, 50, were believed to have hatched the plan to break into the hotel near Chaweng beach. Only one of the nine, identified as Phakjira Payooncharn, 42, was not directly involved in the clean-out but was a purchaser of the stolen items.
All nine are facing serious theft charges with a maximum fine of B140,000 and/or a jail sentence of up to seven years. Police say those who broke into the compound stole 381 items from the buildings and rooms ‒ everything from elevators to toilets, shower heaters, wiring, lamps and curtains.
The resort, which had been closed and locked for months because of a lack of business during the pandemic, was heavily damaged as a result.
Ms Natcha was the wife of a Swiss national who had leased the property from landlord Yommana Poolsawad to build the hotel, according to police.
The owner of the B400mn hotel with 348 rooms had earlier assessed the damage from the theft at B70mn.
Investigators and the property owner re-examined Chaweng Blue Lagoon The Teak Wing Hotel again and found that 1,000 items at the resort were still there. They then revised the damage downward to B14mn baht.
Col Yuthana said the investigation took a turn when officers discovered social media posts by Ms Natcha offering goods for sale. They subsequently called her in for questioning.
Ms Natcha was among the lessees who had rented the site in 1990 on a 30-year lease to construct the hotel in 1990. The property owner did not extend the lease contract after it expired in 2020. They were ordered to remove all goods and return the property to the owner within 30 days.
Owner Yommana hired workers to guard the compound before leaving it unattended after the security contract came to an end. When she checked the hotel on Aug 22 and found many things were gone. She went to register a complaint at Bo Phut Police Station.
It was still unclear why the issue did not come to light until nearly two weeks after the complaint was filed with police.
Col Yuthana said on Tuesday (Sept 6) that the looting was not discovered after it happened because the location of the hotel was not visible from the outside.
Ratchaporn Poonsawat, President of the Koh Samui Tourism Association, praised police for their investigation but said he was not certain that all those involved had been rounded up.
Assistant national police chief Lt Gen Surachate Hakparn said he also suspected more people involved were still at large, and officers had been instructed to expand the scope of the investigation.
The case could erode investor confidence in tourist locations in the country, he added.