Continuing the diatribe, Dr Mahathir Mohamad has asked if 1MDB was involved in money laundering, with the knowledge of its advisor - Prime Minister Najib Abdul Razak.
The former premier questioned if this prompted the money from Cayman Islands to be kept in Singapore.
"Singapore scrutinises all money coming in and going out of the country to prevent money laundering.
"Doesn't 1MDB know about the Monetary Authority of Singapore (MAS) rules? " he asked in his blog post.
Mahathir was responding to Najib's Parliamentary written reply that the US$1.103 billion (RM4 billion) was kept in Singapore instead of Malaysia as Bank Negara would scrutinise all transactions valued at more than RM50 million [ See image at end of article ].
However, Mahathir said banks intervening in such transactions would not be an issue if the transaction was legitimate and not money laundering.
Malaysiakini has contacted 1MDB on the matter and is awaiting response.
Mahathir had zoomed in on the 1MDB's US$1.103 billion after the government issued confusing explanations on the status of the funds.
Ministers check written replies
1MDB had said the money was redeemed in cash from Cayman Islands after an aborted deal with PetroSaudi and later kept in BSI Singapore.
This was also reiterated by Najib in a parliamentary written reply on March 10 but later changed his answer on May 20 that they were in the form of assets.
This became even more baffling when Finance Minister II Husni Hanadzlah clarified the assets were in "units" but refused to explain what he meant.
Mahathir had accused Najib of lying and committing criminal wrongdoing to cover up the matter.
In the blog posting today, Mahathir reiterated this, stating that even though the written reply was prepared by government officials, the minister is ultimately responsible for checking them.
"Government officers which prepare the answers are not immune (to prosecution). They are responsible for the answers.
"If it is found that the answer prepared by them are not based on the truth and valid evidence, they can be prosecuted for attempting to protect the minister by hiding the truth.
"In other words, the minister can be charged for lying the government ministers can be charged together," he said.