Steve Bannon, an architect of President Donald Trump’s 2016 election victory, has been charged with defrauding Trump supporters in a campaign to help build his signature wall along the US-Mexico border, prosecutors said on Thursday.

As a top adviser to Trump’s presidential campaign who later served as White House chief strategist, Bannon helped articulate the Right-wing populism and fierce opposition to immigration.

Bannon was among four people arrested on Thursday and charged with conspiracy to commit wire fraud and conspiracy to commit money laundering in an indictment secured by federal prosecutors in Manhattan. Prosecutors accused the defendants of defrauding hundreds of thousands of donors through a $25 million crowdfunding campaign called “We Build the Wall”.