In what could be the first breakthrough in the investigation over former Prime Minister Yingluck Shinawatra's 'disapearance' almost a month ago, Thai police arrested three of its own men including a colonel last night for suspicion of playing a key role in her escape.

The police also seized a Toyota Camry which the investigators believed was used as the getaway car to ferry Yingluck to the Thai-Cambodian border.

"The three police officers who were interrogated last night gave useful information on the case," said Deputy National Police chief Gen Srivara Rangsibrahmanakul to reporters here, today, adding that the policemen confessed of their involvement.

He confirmed the arrest of the officers last night, including one with the rank of a colonel but declined to divulge further on his identity.

On the suspected getaway car, Srivara said, the investigators were trying to trace the owner of the Toyota Camry, which according to record was last used about five years ago.

Yingluck, the younger sister of exiled former Prime Minister Thaksin Shinawatra was suspected of following her brother's footstep in fleeing abroad after failing to attend a court verdict last month, which could see her being jailed up to ten years if found guilty.

She has not been seen in public or made a statement since her 'disappearance', with the media speculated she is currently in Dubai, United Arab Emirates (UAE) where her exiled brother owned a house there.

The authorities alleged she sneaked out of the country about two days before the verdict via the Thai-Cambodian border to Singapore before flying off to Dubai.

Meanwhile Deputy Prime Minister Gen Prawit Wongsuwan, who oversees internal security matters, also commented on the latest development and said, two cars, a Toyota Camry and Mercedes Benz, were used in Yingluck's escape.

"The Mercedes Benz was used to drive her (to an unidentified location), where the Toyota Camry picked her up and headed to the border. We haven't found the other car (Mercedes Benz)," he said.

Prawit, who is also the Defence Minister, said the police colonel disclosed during interrogation that he was instructed by 'someone', but stopped short of revealing the identity of the mysterious individual to the media.

-- BERNAMA