Anwar Ibrahim, the jailed Malaysian politician who built the alliance that swept to power in last week's general election, has been freed.
Earlier, Anwar was thronged by scores of supporters and reporters after he walked free from a hospital, where he was recovering from shoulder surgery, and whisked away to an audience with Malaysia's king.
Anwar also said he harboured no malice against Dr Mahathir, despite the latter sacking him in 1998, prior to his conviction for sodomy and corruption.
While there were no massive surprises in the summary of the Auditor General's report, and it did not mention former premier Najib Razak by name, the audit said 1MDB officers took investment actions against or without full knowledge of the board of directors on several occasions, while giving inaccurate or conflicting information to stakeholders.
Mahathir has said he expects to run the government for up to two years during an uncertain transition period but has signalled the reins would be turned over to Anwar eventually.
A popular Islamic student leader, Anwar joined the ruling Malay party in 1982, a year after Mahathir became prime minister.
Jailed for six years, Anwar says he was kept in solitary confinement, singing 1960s pop tunes to stay sane and reading anything he could get, including the Quran, the Bible and Shakespeare.
Jack Seng, another supporter wearing a shirt with a logo of Anwar behind bars, said he thought Mahathir and Anwar would resolve any tensions between them.
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I thought maybe we won't score the second goal, but we can not concede - they never crossed the halfway line. He added: "The Champions League final [defeat to Barcelona] was 2006, 12 years ago".
Anwar was imprisoned again in 2015, when Najib was prime minister, after another sodomy charge, which he described as a politically motivated attempt to end his career. Anwar's wife, Wan Azizah, was appointed Malaysia's new deputy prime minister by Mahathir on Saturday.
Mahathir is the leader of the ruling alliance and Anwar's People's Justice Party (PKR) won the majority of parliamentary seats in the group.
"Overall, corporate governance and internal controls in 1MDB were less than satisfactory", the summary said.
He said that Anwar, a former enemy turned ally, may be just a member of parliament for a while.
He refused to go quietly, leading tens of thousands of demonstrators in street rallies in Kuala Lumpur demanding reforms before being arrested.
It was Anwar's second spell in prison. He led an opposition alliance to major gains in the last two elections, winning the popular vote in 2013. Faced with a reinvigorated opposition, the government used all the levers of power to further tilt the playing field in its favor, critics and analysts said.
Four days after Malaysia said it will reopen a graft probe into state fund 1MDB, Swiss prosecutors said they wanted to start talks with investigators in the Southeast Asian nation as soon as possible to better coordinate various criminal probes into the sprawling case. The fund was set up by Najib in 2009 to promote economic development but accumulated billions in debt.