KUALA LUMPUR, June 29 ― Datuk Seri Dr Wan Junaidi Tuanku Jaafar said today it was logical for the authorities here to believe claims that the documents leaked by the arrested former PetroSaudi International (PSI) director Xavier Justo were doctored.

Explaining this, the deputy home minister pointed out that the documents on the oil firm’s now-aborted deal with 1Malaysia Development Berhad (1MDB) were seen to have originated from Justo, who is currently being investigated for blackmail and extortion by the Thai police.

“Document is seen to be from him, so we cannot assume anything else other than him tampering the document… of course everything that we do and say here is based on logical assumption,” he said.

Wan Junaidi acknowledged that the Thai police have not specifically claimed that the documents were tampered, but said this was likely because they did not want to speculate on their own ongoing investigation.

“Investigating authorities would not make any speculation in their papers, perhaps it will be when they bring to court later, but not before. That is to protect their credibility,” he said.

Justo, a Swiss national, was arrested by the Thai police last Monday.

He was allegedly the source of leaked documents on PetroSaudi’s US$1.2 billion (RM4.5 billion) joint venture with 1MDB that fell through in 2009.

Home Minister Datuk Seri Ahmad Zahid Hamidi said later that  the authorities will investigate business paper The Edge for publishing purportedly unverified news on 1MDB’s aborted joint venture with PetroSaudi after Justo’s arrest.