KUALA LUMPUR (THE STAR/ASIA NEWS NETWORK) - Malaysia's police headquarters at Bukit Aman will call in several individuals for questioning over the Thai police's recent revelation that Swiss citizen Xavier Andre Justo had identified a group of people who bought documents from him to use to attack Prime Minister Najib Razak.

These people include a Malaysian opposition leader and a media boss.

Inspector-General of Police Tan Sri Khalid Abu Bakar said the information revealed by their counterparts in Thailand was shocking and serious.

"A police report has been lodged based on the revealed information so that we can conduct investigations here.

"We have identified the opposition leader involved and several other individuals who will need to come in soon to have their statements recorded," he told reporters during the Hari Raya Aidilfitri open house at Bukit Aman on Friday.

He hoped everyone involved would give their full cooperation to police during the course of investigations.

"Those who do not cooperate will be arrested and remanded to assist investigations.

"We also encourage anyone with documents pertaining to this case to come forward immediately before we go after them," he warned.

It was reported recently that Justo, who is under investigation by Thai police for allegedly blackmailing PetroSaudi International, has admitted to meeting certain individuals in Singapore to negotiate the handing over of documents in his possession.

Royal Thai Police spokesman Pol Lt Gen Prawuth Thavornsiri told reporters in Bangkok on Thursday that Justo met with very important people from some country, in Singapore.

Prawuth said Justo negotiated the price to give them all the copies of the documents in electronic files.