Alan Dershowitz, an ally of U.S. President Donald Trump, and former FBI director Louis Freeh have officially registered with the U.S. government as lobbyists for Dan Gertler, an Israeli billionaire known for shady deals and corruption accusations.

The filing, which was first reported by U.S. network CNBC, will allow the two major Washington figures to advocate on behalf of Gertler, who has been under sanctions from the U.S. treasury since 2017.

According to CNBC, Dershowitz, who has never been registered as a lobbyist before, said he was only acting as Gertler's lawyer.

The lobbying registration, despite only being released now, records the effective start date as October 17, 2018. Dershowitz was advising Gertler as early as last year, according to a New York Times report.

The decision to hire lobbyists is not surprising in itself. “He’s an international businessman and it’s very difficult to do business internationally” when under sanctions, Peter Jones, a campaign leader at international NGO Global Witness, told Al-Monitor.

The place of both Dershowitz and Freeh in Washington and their relationship to the current administration are significant, however.

Louis Freeh, who is also an attorney, was FBI director between 1993 and 2001. He registered to act as a lobbyist for the first time in March this year, but is known to have ties with other controversial figures. This includes former New York mayor and Trump lawyer Rudy Giuliani, whom Freeh hired to pressure the Romanian president, according to a report in The Independent, in connection with Hunter Biden.

Dershowitz has been an ally of both Donald Trump and Benjamin Netanyahu, coming out publicly, including in Haaretz, to dispute the accusations of corruption against Israel's embattled premier. He has come under scrutiny for his links to disgraced financier Jeffrey Epstein.

The original sanctions against Gertler said he "amassed his fortune through hundreds of millions of dollars’ worth of opaque and corrupt mining and oil deals in the Democratic Republic of the Congo," mainly through his personal relationship with former President Joseph Kabila.

Open gallery view Dan Gertler and former Israeli Prime Minister Ehud Olmert, April 28, 2005 Credit: Tomer Appelbaum

"As a result, between 2010 and 2012 alone, the DRC reportedly lost over $1.36 billion in revenues from the underpricing of mining assets that were sold to offshore companies linked to Gertler," a Treasury statement said.

Gertler's name came up more than 200 times in the 2016 leaks of financial documents known as the Panama Papers, providing an insight in the complex network of ways in which the tycoon attempted to hide some of his money.

The leaks also showed attempts to bribe Yisrael Beiteinu chairman - and current electoral kingmaker - Avigdor Lieberman in 2011.