BANGKOK • The authorities in Thailand are closing in on the people who helped ousted prime minister Yingluck Shinawatra flee the country last month, Deputy Prime Minister Prawit Wongsuwan said yesterday.

Yingluck, 50, whose government was ousted by the military in 2014, disappeared from Thailand shortly before a Supreme Court verdict in a negligence case against her.

Mr Prawit told the media that Yingluck left Thailand by crossing to neighbouring Cambodia by land via the Aranyaprathet border district in Sa Kaeo province, almost 300km east of the capital Bangkok.

He said the authorities had seized a vehicle believed to have been used to take Yingluck to the Cambodian border. It was found near a house in Nakhon Pathom province, north of Bangkok.

Police said the owner, based on the car registration, did not match the person who had the car at the time. Three police officers were questioned on Thursday night. Mr Prawit said the three men admitted to helping drive Yingluck to the border, but no charges have yet been filed.

"All three of them gave us useful information. We are working on the investigation and consolidation of the evidence," deputy national police chief, General Srivara Rangsibrahmanakul, said.

A police source who did not wish to be named said the ongoing investigation has revealed that a former police chief with a close relationship to the Shinawatra family had masterminded Yingluck's escape.

Meanwhile, the caretaker secretary-general of Pheu Thai Party, Mr Phumtham Wechayachai, yesterday urged the authorities to show clear evidence whether policemen who were interrogated were involved in the flight of Yingluck. He asked for evidence such as pictures showing Yingluck in the suspected car or the detained suspects, driving the car. "I can only hope that those who have been interrogated are not scapegoats," he told The Nation.

Yingluck's whereabouts remain unknown. She has not made any public appearance since Aug 23, but there are widespread reports that she is with her brother Thaksin, who lives in self-exile in Dubai.

The Supreme Court has issued an arrest warrant for Yingluck and rescheduled the verdict for her negligence case to Sept 27.

Yingluck faces up to 10 years in prison if found guilty of negligence over a costly rice subsidy scheme that helped bring her to power in a 2011 general election.

She has accused the military government of political persecution and pleaded innocent to the negligence charge.

REUTERS, THE NATION/ ASIA NEWS NETWORK