Soukanh Visathep, 65, and Somvang Keomanyvong, 61 were shot dead on Wednesday evening as they arrived by bus at an Ubon Ratchathani bus station from Laos' southern Champasak province.

A gunman shot them with a .38 revolver pistol at the heads while they were picking belongings from the bus.

Background information from relatives who traveled with the pair indicated that they were security officers of Laos's previous regime before the fall of Vientiane in 1975.

Soukanh was a former police at Vang Tao checkpoint in Champasak while Somvang was a soldier of Lao Royal Army in Champasak's Pakse district.

Judged by their background and frequent travelling to neighbouring Laos, the two might link to an anti-Vientiane movement, said Ubon Ratchathani's deputy police chief Pol Col Kriangsak Rasasat.

The gunman was expectedly in the same ring of those who killed many member of the anti-Lao government, he added.

However, business or personal conflict might be motivation of the murder as well, police said.

Khammai Visathep, a younger brother of Soukanh said the two are brother-in-law have fled from home more than 30 years ago. They run a small business of making picture frame in the US, he said.

He noted the business is too small to cause any serious conflict that might lead to a murder. Khammai did not disclose whether the two had any connections with anti-Vientiane movement.

Many members of anti-Lao communist movement were shot dead in Thailand's border provinces in couple of years and some suspected Thai gunmen were brought into justice over the past months.

The Lao government consistently denied any linkage of murder in Thailand.

The Nation