Xavier Andre Justo, currently under investigation by the Thai police for allegedly blackmailing his ex-employer PetroSaudi, has admitted to meeting with some people in Singapore to negotiate the handing over of PetroSaudi documents in his possession, according to Thai police.

"He met with very important people from some country in Singapore. He negotiated about the price to give them all the copies of the documents in electronic files," Royal Thai Police spokesman Pol Lt Gen Prawuth Thavornsiri told reporters here Thursday.

He said Thai police knew the identity of the people that Justo had met based on his own admission as well as evidence collected and details from sources such as Justo's cellphone and personal computer.

He, however, declined to reveal who Justo had met.

When asked if Justo had met with Sarawak Report news portal editor and founder Clare Rewcastle Brown, Prawuth just replied: "There was also someone sent from Europe."

Justo was reported in the Malaysian media as having met with members of a Malaysian opposition group and a media owner in Singapore prior to his arrest in Thailand on June 22.

However, Prawuth said Justo denied tampering with or changing the original documents.

"He (Justo) didn't change. He gave them the original documents in electronic files," Prawuth said when asked if Justo admitted to tampering with the documents.

He also raised the possibility that the group which had bought the copies of the original documents tampered with it as there were changes in information compared with the original emails that Justo stole.

He said Justo's case was almost completed and would not take more than a month more as he already admitted to blackmailing PetroSaudi.

He said the Thai police had gathered other documentary evidence, such as emails and immigration and hotel reports.

The Thai police had no plans to interview other witnesses as they had enough evidence now, he said.

Prawuth was unsure when Justo would be charged, but it had to be within 84 days from the date of his arrest on June 22.

He said Justo would not be extradited as the offence was committed in Thailand.