The National Anti-Corruption Commission (NACC) on Thursday found itself in the hot seat after it cleared Deputy Prime Minister Prawit Wongsuwon of wrongdoing in the luxury watch scandal, ruling by a majority vote that he did not make a false asset declaration.

Addressing a press conference on Thursday afternoon, NACC secretary-general Worawit Sookboon said the commission ruled 5:3 there were no grounds to accusations that the deputy premier falsely declared his wealth when he did not include 22 luxury watches and rings in his list of assets.

Deputy Prime Minister Prawit Wongsuwon wearing one of the expensive watches. Chanat Katanyu

NACC chairman Watcharapol Prasarnrajkit, who is a former close aide of Gen Prawit, recused himself from the meeting in which Gen Prawit was the sole item on the agenda.

The probe was launched when Gen Prawit was spotted wearing a platinum Richard Mille RM 029 valued at about 2.5 million baht, and a diamond ring at a Government House event on Dec 4, 2017. These items and other watches which came to light later were omitted from Gen Prawit's assets declaration to the NACC. Gen Prawit claimed the luxury watches belonged to friends and were all returned.

Mana Nimitmongkol, secretary-general of the Anti-Corruption Organisation of Thailand, said the NACC failed to show transparency in investigating the case. It did not say what the charges were and initially declared Gen Prawit did not evade asset declaration. It was only after reporters asked whether he could be violating the law about accepting a gift of over 3,000 baht that the NACC said it was another issue.

"It was like 'catch me if you can', then the NACC will speak out," he said.

He also questioned the investigation process and conclusions of the NACC. "We can ask whether the laws contained loopholes for the asset declaration requirement. In that case, the laws need to be amended," he said, adding that he wanted to see the individual verdict report of the five NACC members who cleared Gen Prawit of wrongdoing, and the three members who only said there was not enough evidence.

"In the justice procedure, the defendants can say anything but it depends on whether police seek to find the truth or not. Likewise, today we have to look into how the NACC works. But for the defendant, society has judged him already," Mr Mana said.

The ruling was also denounced by rights activist Thicha Nanakorn who demanded Gen Prawit's resignation after the scandal broke and stepped up calls for the NACC to speed up the long-delayed probe. "This unscrupulous act by the NACC and the political office-holder will go down in history. It may look like a win-win, but it is a defeat," she wrote on Facebook after the ruling was made.

The former member of the now-dissolved National Reform Council also launched an online campaign in which 81,000 people signed a petition calling on Gen Prawit to quit. As of 8.40pm on Thursday, there were 435 comments on the Facebook of CSI LA, a page that compiled pictures of different luxury watches worn by Gen Prawit. Most of the comments criticised the NACC or Gen Prawit.

According to Mr Worawit, the NACC investigators sought clarification from Gen Prawit on four occasions and were told the watches had been borrowed from a close friend, Patthawat Suksriwong, and returned. The rings were given to him by his parents and some were considered lucky charms.

In its probe, the NACC sought information from various sources including local dealers of luxury brand watches, the Customs Department, the Foreign Ministry, and from overseas luxury watch manufacturers.

The NACC found that Mr Patthawat, now deceased, was a wealthy businessman and a collector of luxury watches and the number of watches in his possession exceeded the 22 items under investigation. Based on interviews, Mr Patthawat lent watches to his old friends, including Gen Prawit, and also offered financial help to those in need, he said.

At Mr Patthawat's residence, the NACC found 20 luxury watches and a warranty for another watch that Gen Prawit was seen wearing in the pictures shared by the media. The investigators found Mr Patthawat bought one from a dealer overseas and two from other people. The NACC could not find purchase documents for the remaining watches and with dealers overseas refusing to give information the agency could not verify the origin of the rest.

Under the Civil and Commerce Code, the 21 luxury watches found at Mr Patthawat's residence were assumed to belong to Mr Patthawat. So the NACC concluded he had lent the 21 watches to Gen Prawit. As for the 22nd watch, the NACC assumed that Gen Prawit had also borrowed it from Mr Patthawat.