Steve Bannon, the former chief strategist of President Donald Trump, has been arrested and charged with conspiracy to commit wire fraud.
The US Department of Justice said the charge relates to We Build The Wall, a fundraising campaign to support the building of a border wall between the US and Mexico.
Federal prosecutors alleged that Bannon, along with three others, “orchestrated a scheme to defraud hundreds of thousands of donors” in connection with the online crowdfunding campaign that raised more than $25m (£19m).
A spokeswoman for Bannon did not immediately respond to a request for comment.
The charges were contained in an indictment unsealed in Manhattan federal court.
According to the indictment, Bannon promised that 100% of the money donated would be used for the project, but the defendants allegedly used hundreds of thousands of dollars in a manner inconsistent with the organisation’s public representations.
The trio allegedly faked invoices and sham “vendor” arrangements in a bid to hide what was really happening, the indictment added.
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Bannon was appointed chief executive of Mr Trump’s successful presidential campaign in 2016, leaving his role at conservative website Breitbart News to join the campaign.
He became chief strategist for Mr Trump after his inauguration, but Bannon clashed with others in the White House and was pushed out in August 2017.
Bannon returned to Breitbart, but left again the following year after being quoted in Michael Wolff’s explosive book, Fire And Fury: Inside The Trump White House.
He was quoted questioning his former boss’ mental stability and claimed those close to the president described him as a “moron, an idiot”.
Bannon later expressed “regret” over his place in the book.