Swiss attorney-general Michael Lauber says Mohamed Apandi Ali had refused to extend his cooperation when the latter headed the Attorney-General's Chambers.
Lauber said this after meeting with Apandi's successor Tommy Thomas yesterday.
"Since 2015, (we have been) conducting our investigations in Switzerland and from the beginning, we tried to cooperate very closely together with the United States, Singapore, Luxembourg.
"And we also tried (to cooperate) with Malaysia, but at that time, in 2016, we got confirmation that the Malaysian attorney-general that time didn't want to cooperate with us," he stated.
Switzerland's Office of the Attorney General (OAG) had requested for mutual legal assistance from Malaysia on two occasions, but received no response in return.
Apandi was appointed as attorney-general on July 2015. His appointment followed the removal of Abdul Gani Patail from the post just as he was preparing to bring charges against then prime minister Najib Abdul Razak over the 1MDB scandals.
He subsequently cleared Najib of any wrongdoing in January 2016 concerning the RM2.6 billion 'donation' and RM42 million from SRC International Sdn Bhd transferred into the former premier's personal bank accounts.
SRC was a subsidiary of the 1MDB state investment firm founded by Najib.
In the May 9 general election, Najib led the BN coalition to defeat for the first time in 61 years since independence.
Following the installation of a new government, Prime Minister Dr Mahahir Mohamad accused Apandi of a cover-up and the latter was made to go on leave.
Najib was finally charged on July 4 with three counts of criminal breach of trust and one count of abuse of power in relation to transactions involving SRC International.
The first three were the same charges MACC had recommended Gani bring against Najib before he was dismissed.
The charges against Najib were specific to transactions made in Malaysia.
The wider 1MDB investigation, which involves multiple international jurisdictions, is still ongoing.