Abu Dhabi authorities have arrested former finance official Khadem Al Qubaisi over his role in an alleged multibillion-dollar fraud related to Malaysian state-run fund 1MDB, the Wall Street Journal reported, citing people familiar with the matter.

The arrest was made last week and no charges have yet been filed. Al Qubaisi formerly headed up Abu Dhabi's International Petroleum Investment Company, which owns Falcon Private Bank in Switzerland. That bank has reportedly been banned by Singapore's financial regulator from taking on new business in the city-state. Falcon could not be reached for comment on that report, while the Monetary Authority of Singapore declined to comment.

Swiss authorities are already probing Al Qubaisi over the alleged plot to divert funds intended for 1MDB, which was set up in 2009 to drive initiatives for long-term economic development in Malaysia. 

In July, the US Justice Department alleged Al Qubaisi was part of a conspiracy to misappropriate about $1.37 bilion from a pair of IPIC-guaranteed bonds issued by 1MDB in 2012 and totalling $3.5 billion, the Financial Times reported. The department filed civil lawsuits last month seeking to freeze about $100 million of real estate in the US that Al Qubaisi allegedly bought with stolen 1MDB money in what the department says is a $470 million trail stretching from Malaysia to Abu Dhabi to the British Virgin Islands.

US investigators have now widened their probe into Al Qubaisi’s part in the alleged fraud to look for connections to Hakkasan Ltd, a London-based company that runs a string of nightclubs in Las Vegas, the WSJ quoted the people as having said. Hakkasan, which reportedly has two $100 million venues, is controlled by Sheikh Mansour Bin Zayed Al Nahyan, deputy prime minister of the United Arab Emirates and member of the Abu Dhabi royal family. The people added that the investigation is focused on Al Qubaisi’s actions and there is no allegation of any wrongdoing against Hakkasan or its employees.