KUALA LUMPUR • Former premier Mahathir Mohamad said in a short video clip that he is not "Malaysian Official 1".
Opposition veteran Lim Kit Siang wrote in his blog that he, too, is not the unnamed official.
The term "Malaysian Official 1" was highlighted 36 times by the United States Department of Justice (DOJ) in its civil lawsuits and is now a hot topic on social media. So who is this mysterious person?
Internet memes have been created based on this since news spread of the US legal action taken last Wednesday involving money siphoned from state fund 1Malaysia Development Bhd (1MDB).
Tun Dr Mahathir, in the video clip put up by a non-governmental organisation, raised both his palms and said: "I am not Malaysian Official 1. I think, who is, you can decide from the description of 'Malaysian Official 1' found in the report by the Justice Department in America."
Mr Lim wrote in his blog: "Let me clearly and formally declare that I am not the Malaysian Official 1. Will the Prime Minister, Datuk Seri Najib Razak, similarly state his position... "
In the Twitter hashtag #MalaysianOfficial1, some asked: "Will the real Malaysian Official 1 please stand up?"
The suits filed by the DOJ allege that US$681 million (S$925 million) from a 2013 bond sale by 1MDB was transferred to an account belonging to Malaysian Official 1.
The person, according to the DOJ, is "a relative of" Mr Najib's stepson Riza Aziz - a key figure mentioned in the civil lawsuits to seize assets in the US believed to have been procured using 1MDB funds.
The person, the DOJ said, is also "a high-ranking official in the Malaysian government who also held a position of authority with 1MDB".
US Attorney-General Loretta Lynch, asked by a reporter last Wednesday, declined to address speculation that Mr Najib was Malaysia Official 1.
Ex-deputy prime minister Muhyiddin Yassin - sacked by Mr Najib a year ago for asking questions about 1MDB - said he has no doubts who this unnamed person is.
"It was clearly stated in the DOJ report that this person had US$681 million in his private account in AmBank Malaysia," Tan Sri Muhyiddin said last Friday. "We don't know of any other apart from Najib who was reported to have that amount of money in his personal account with AmBank."
Mr Najib has always maintained he had not done anything wrong.
Attorney-General Mohamed Apandi Ali said last Thursday: "There has been no evidence from any investigation conducted by any law enforcement agencies in various jurisdictions which shows that money has been misappropriated from 1MDB (or) criminal charges preferred against any individuals for the offence."