The owner of a jewellery trading company on Thursday offered a 500,000-baht reward for information leading to the recovery of gems worth more than 10 million baht stolen on Wednesday morning.
Wanich Wongsuabchart, 27, of Piyamitr Co, said the missing gems were stolen on Wednesday at 5am while in the safekeeping of Malca-Amit Secured Transport (Thailand) Ltd on the day they were to be displayed at the 58th Bangkok Gems & Jewelry Fair 2016 at Impact Muang Thong Thani.
Mr Wanich said Malca-Amit Secured Transport was hired by the company to look after four boxes of gems as it attended the gems and jewelry fair for the first time.
The Malca-Amit employees collected the four 30x30x20cm boxes from Piyamitr Co at 5pm on Tuesday.
Mr Wanich said two of the four boxes had been opened and 32 gem items weighing 440 grammes inside were missing. The theft took place at 5am but the company did not inform him until 11am. He did not give details about how the gems were stolen.
The missing gems were covered under a 10 million baht insurance contract with Malca-Amit. But Mr Wanich said some of them had been in his company's possession for a long time and he wanted them back.
He offered 500,000 baht to anyone who can give information leading to the recovery of the missing precious stones.
Malca-Amit has filed a complaint at Yannawa police station, Mr Wanich said, adding he has used the services of the company several times.
Late Wednesday night police arrested five Filipinos on charges of stealing a diamond necklace worth about 300,000 baht from the same fair.
Canoy Carpio, 58, Ebueza Carpio, 27, Bien Mulobuko, 27, Mallari Candelaria, 56, and Champoco Velarde, 65, were arrested at Don Mueang airport at 11.30pm on Wednesday with the necklace in their baggage as they were arranging for a departure flight.
The group arrived in Thailand on Monday and the theft took place at the fair on Wednesday, tourist police commander Pol Maj Gen Surachet Hakpan said.
They had return fares for next Monday, a day after the fair ended on Sunday, he said.
Police have stepped up security measures at the venue.