Cambodian immigration officer Leang Piseth, who is detained in Thailand on suspicion of smuggling weapons, is a relative by marriage of Defence Minister Tea Banh, as well as of recently reassigned Koh Kong Provincial Governor Bun Leut and retired high-ranking Police General Tham Sann, The Post has learned.

The previously unreported family links between the senior officials and Piseth, a lieutenant in the Interior Ministry’s General Department of Immigration, were confirmed in interviews with his relatives and officials in Koh Kong province late last week.

Piseth, who has been in Thai custody for more than two weeks, is the son-in-law of Tham Sann, the retired Interior Ministry undersecretary of state and ex-deputy provincial governor of Koh Kong who is Banh’s brother-in-law, Sann confirmed during an interview at his home on Friday.

Sann’s family has deep roots in Koh Kong province. His younger brother, Bun Leut, ended a seven-year stint as provincial governor this week. He was reassigned as a government adviser with a rank equivalent to minister, as part of a broader reshuffling of provincial governors, according to a decree released online.

Piseth was arrested in Thailand’s Trat province near the border with Cambodia’s Koh Kong province on June 3 when his white Range Rover was seized near the crashed car of Thai air force officer Phakhin Detphong, who was discovered to be transporting a cache of AK-47s, machine guns, explosives and ammunition.

While no evidence links Piseth’s high-ranking in-laws to the smuggling case, the family connections raise questions about the investigation into the officer’s involvement in the alleged arms trafficking.

One local policeman in Koh Kong, who requested anonymity, said he believed the immigration officer’s well-known “powerful” family connections shielded him from scrutiny in Cambodia.

Banh has already vehemently denied being connected to the alleged smuggling in response to reports in the Thai-language media, calling the articles “false” and demanding an apology from the outlets in a letter to the Thai defence attaché office at the country’s embassy in Phnom Penh.

Thai authorities have contended the guns were smuggled from Cambodia and destined for ethnic Karen rebels in Myanmar, according to English-language Thai press.

Banh has said the Defence Ministry, which he oversees, will investigate the case, and has denied to the Cambodia Daily that Piseth was an official, and that the guns found by Thai authorities had come from the Kingdom.

Piseth’s employment at the General Department of Immigration was confirmed by the department head, Sok Phal, as well as by other immigration and police officials in Koh Kong province.

Reached yesterday, Banh, who is also a deputy prime minister, reacted angrily to questions about his relationship with Piseth, acknowledging they were related by marriage but reiterating that he had no connection to his in-law’s activities.

“I do not have any involvement with it. It is his business, done somewhere else, so why come to ask me?” said Banh, who declined to give further details about the ministry’s investigation into the case.

“Even if I investigate, I would not report to you because we have our work to do and why do we have to report to a journalist?”

Sann, Banh’s brother-in-law, also denied having any knowledge about his son-in-law’s case. He said he retired from his role at the Interior Ministry six years ago.

He claimed he was not concerned about Piseth’s current detainment and said he had not spoken with Banh about the matter.

“I do not know, I live in a separate house [from the family property],” said Sann. “This does not involve me.”

Thai authorities have said Piseth was detained on suspicion of involvement in weapons smuggling, though few details have emerged about any role he played in the alleged operation.

Thai-language media, however, have reported that a search of Piseth’s Range Rover also uncovered four firearms.

Sok Phal, chief of immigration, previously told The Post that Piseth was from a “powerful” family in Koh Kong and was recently transferred to his department from the provincial police force and was yet to be assigned a unit.

Reached yesterday, Koh Kong Provincial Police Chief Sam Keath Veat declined to discuss Piseth’s time with his department.

“This is an internal secret of the police,” he said, adding he had received no updates about the case from Thai authorities.

Several people spoken to in Koh Kong were unable to describe what Piseth’s role was with the Immigration Department. Sann, his father-in-law, would only say his in-law moved “back and forth” between the coastal province and Phnom Penh as part of his job.

Speaking from his home in Koh Kong, Piseth’s brother-in-law, Sour Samnang, 45, said he knew little of his relative’s work except that he had been a police officer for four or five years.

“I haven’t seen him in two or three months. We are not really close. I don’t know what he does – just immigration police,” he said, adding Piseth was originally from Koh Rong in Preah Sihanouk and that his parents had died.

“Thailand does not allow us to see him. We just learn it’s related to weapons, we do not know anything.”

At Koh Kong’s Cham Yeam International Checkpoint on Friday, Major You Phal, an immigration officer, said Piseth was not based on the border, but went infrequently to Thailand for “his wife’s business”.

The deputy chief of the checkpoint, Kim Ratana, yesterday said Piseth was still detained in Trat Provincial Prison.Speaking yesterday by phone, former Koh Kong Governor Bun Leut said he was aware of his in-law’s detainment but distanced provincial authorities from the case.

“He was not involved with our authorities because he was not an official within the Koh Kong provincial framework,” Leut said.“I do not feel bad about the arrest because if he has done wrong, the arrest complies with [Thailand’s] law, so we cannot put our hand in.”

A local police officer in Koh Kong province said it was well known in the province that Piseth was well-connected and “rich and powerful”.

This gave him protection from scrutiny, claimed the officer, who requested anonymity for fear of repercussions for speaking about the case.

“We do not pay attention to him because he was police and he is rich and powerful and has enough to live comfortably,” the officer said, adding that Piseth was also known to trade in cars and motorbikes.

“First he is the son-in-law of an undersecretary of state and a nephew-in-law to the provincial governor and deputy prime minister, so we do not think about the crime.”