According to a press release from the Attorney General's office, an investigation by the Malaysian Anti-Corruption Commission
(MACC) found that RM2.03 billion ($620 million) was freely given to Najib by the Saudi royal family, a fact apparently corroborated by the donor during witness testimony.
It was given to him "without any consideration," the report concludes, and says that the sum was returned by Najib in August 2013 because it was "not utilized."
"I am satisfied that there is no evidence to show that the donation was a form of gratification given corruptly," the statement from Attorney General Apandi Ali reads. It also asserts that no criminal offense had been committed, and that Apandi was instructing the Commission to close the investigation.
The MACC also cleared Najib of wrongdoing over government guarantees on RM4 billion ($931 million) of loans to a state-owned company called SRC International from a governmental retirement fund called Kumpulan Wang Persaraan (KWAP), and allegations that the Prime Minister had personally profited from the decision.
Ali's report determined that the Prime Minister had not financially benefited from the cabinet decision.
"MACC itself admitted that based on their investigation, there are (sic) no evidence from the witnesses that could show that (Najib) had committed any act of corrupt practice," it said.
The claims, which go back to July and relate to transfers made as far back as 2013, came to a head in September 2015 when angry street protests
called for Najib's ouster.
The protests came to a boil after a Swiss investigation announced it was freezing funds in accounts held in Switzerland
At the center of the graft scandal was the 1Malaysia Development Berhad (1MDB) fund, which was founded, and is chaired, by Najib. 1MDB, which is wholly owned by the Malaysian government, was formed in 2009 to invest in property, infrastructure and energy projects.
In July 2015, the Wall Street Journal, citing investigative documents from a government probe into the fund, found transfers totaling $681 million from a company in the British Virgin Islands, to accounts investigators believed belong to the Prime Minster.
1MDB insisted in a statement that "the company has never provided any funds to the Prime Minister."
Najib strongly denied the claims.