PetroSaudi whistleblower Xavier Justo was tightlipped about his second meeting with Prime Minister Dr Mahathir Mohamad today.

However, the Swiss national had kind words for the 92-year-old leader.

"I will not comment on any meeting that could have taken place. I just want to repeat that meeting your prime minister is a moment that I will keep in my heart forever.

"Under his guidance and with his wisdom Malaysia has only one direction possible and that is - success," he told Malaysiakini when contacted.

Earlier today, Justo reportedly met Mahathir for around an hour and 15 minutes at his Perdana Leadership Foundation office in Putrajaya.

Yesterday, Justo had also met Mahathir for over an hour at the prime minister's private residence in Serdang.

The PetroSaudi phase, according to the US Department of Justice, was the first of four phases in which 1MDB's funds were allegedly siphoned.

In this phase, at least US$1.03 billion intended for a joint-venture between 1MDB and PetroSaudi was diverted to Good Star Limited owned by businessperson Low Taek Jho between 2009 to 2011.

Sarawak Report was the first to expose this transaction based on the leaked information from Justo, which had at that time was met with scepticism.

Xavier was pursued by PetroSaudi officials in Thailand and he was subsequently arrested and jailed for three years in 2015 for blackmailing his former employer.

However, Justo was freed in late 2016 on a royal amnesty.

The 1MDB scandal is now subject to an international investigation.