Thai police will not summon more people in connection with the case of Swiss national Xavier Andre Justo who is accused of blackmailing his former employer PetroSaudi International.

"Those activities did not take place in Thailand. It was an explanation on the links of this case but those offences did not take place in Thailand at all," Thai police spokesman Pol Lt-Gen Prawuth Thavornsiri told reporters here Wednesday.

He was asked about the disclosure last week that Justo met at least 10 people in Singapore and other places, and whether these people would be summoned for questioning.

Justo was said to have met them to discuss and negotiate the price for handing copies of documents on PetroSaudi International's dealing with 1Malaysia Development Bhd.

Only Justo, who has admitted to blackmailing PetroSaudi International, has been questioned in the case.

Prawuth said the Thai police were in the final steps of collecting evidence for the case but no date had been fixed to charge Justo.

"I think it will be not more than a month, but I don't want to put pressure on the investigation officers. If I say in 10 days then they (investigation officers) might be under pressure," he said.

Thai police still have about 54 days to charge Justo, who as of today has been in Thai police custody for exactly 30 days.

Prawuth said Justo chose his lawyer by himself but did not know who he chosen to represent him.

He said copies of all documentary evidence including e-mails communications in connection with the case had been made for "Justo's safety". When asked what he meant by that, Prawuth explained the copies (of the evidence) were necessary as only Justo knew about the evidence in the case, and if something happened to him, without the copies, it may benefit someone else.

He said Justo was fine and was not under stress.

"I checked with the prison officials as we were worried about his welfare and he is an important witness in this case," he added.

Prawuth said Thai police had not handed any copies of the documents relating to the case to the Malaysian police, and that he still do not know when it will happen.

"It is in the process of being coordinated," he said.

Asked about Malaysian police's request to interrogate Justo, Prawuth said they may have contacted the Thai government via the ministries of Foreign Affairs on this.

"However, Thai police have not been informed yet," he added.