BANGKOK • The Thai police have said they are considering suing a former senior officer investigating human trafficking for defamation over comments he made implicating senior officials in the trade.

Former police major-general Paween Pongsirin arrived in Melbourne a few days ago on a tourist visa, and told the Australian Broadcasting Corp (ABC) on Thursday that he feared for his life because influential figures in the Thai government, military and police implicated in the illicit trade want him dead.

He also said he is seeking political asylum in Australia as he fears for his life if he goes home, according to the ABC.

"There must be some place, some safe place for me," he said in the interview. "I came here because Australia is a safe place."

Royal Thai Police chief Jakthip Chaijinda told reporters yesterday that he did not know why Mr Paween had fled, but said a legal team was checking whether his comments were defamatory.

"I don't know the reason why he had to go and speak about this issue but he should not talk about this because it could damage the country," he said.

Mr Paween resigned from his post as deputy commissioner of Provincial Police Region 8 last month, saying an order to transfer him to Thailand's south would expose him to revenge by members of trafficking syndicates still at large. He flew to Singapore in mid-November and travelled to Australia on Dec 5.

Suspects he was investigating for trafficking were influential in the region, he said, and could target him.

Mr Paween had led an investigation into a mass grave containing at least 36 bodies that was discovered in May hidden deep in a mountain near the Thailand-Malaysia border.

That inquiry resulted in charges against 88 people, including a lieutenant-general in the Thai army, Manas Kongpan, who is accused of being a trafficking kingpin.

Mr Paween was listed as a key witness in the case.

"We issued 153 warrants across all areas and that included government officials... I had to do just my duty, not to think of danger or trouble, but now I realise how dangerous it was," he said.

"There are bad police and bad military officers, and I know they are trying to get me," he told the New York Times by phone from Australia.

Mr Paween said he had faced growing demands from powerful people that he end his investigation. "There are not many times we'll see the arrest of a military general," he said. "They are upset. They lose face."

Mr Paween said he had received calls from angry superiors and people who warned him he was facing great risk. Soon after he submitted the case to prosecutors, he said, he was ordered to relocate to Thailand's deep south.

When he asked for another posting, he said, it was refused. He resigned after allegedly receiving death threats, he added. "No one can protect me now. There is no sympathy, or mercy, for me from my bosses," he said.

"Even after I resigned from the service, nobody seemed to care. So I decided to bring my family to Australia immediately."

The Thai police have not been informed of any threats to him, police spokesman Dejnarong Suthicharnbancha said on Thursday. "Paween should have sent a complaint to his supervisor for investigation."

Mr Paween's resignation raised serious questions over the extent of collusion between crime syndicates and the authorities, and prompted criticism that an officer had little chance of success in tackling corruption among the police and armed forces.

"A good person has no place in this country," a columnist in the newspaper Thai Rath wrote.

"He was brought in as a hard-nosed experienced investigator, someone who has a reputation for being incorruptible," Mr Phil Robertson of Human Rights Watch Asia told the ABC.

"He was pursuing leads, and he felt there was a lot more information to be got... Obviously that got to be too much for some people."

Ms Amy Smith, executive director of human rights group Fortify Rights, said in a statement: "This trial is a test of Thailand's commitment to end human trafficking, and the prognosis isn't looking good. Investigators should be supported to combat human trafficking in Thailand, not be forced into hiding."

But Mr Paween said despite his experience, he hoped the anti-trafficking work would continue.

"I can't handle the cases any more, but I think the prosecutor and the judge are trying their best in their situation, as well as the witnesses and my team."

REUTERS, NEW YORK TIMES, AGENCE FRANCE-PRESSE, THE NATION/ASIA NEWS NETWORK