In a letter sent on Friday, several watchdog groups called on the U.S. Department of Justice to investigate whether Donald Trump‘s campaign is “engaging in knowing and willful violations of federal campaign finance laws.” The complaints stem from allegations that Trump’s campaign continues to solicit illegal donations from foreign nationals.

Last month, the Campaign Legal Center filed a complaint with the FEC after Trump’s campaign reportedly sent dozens of prominent Icelandic, Scottish, Australian and British politicians fundraising emails seeking donations. Trump was trying to drum up support after the recent ‘Brexit’ vote in which the U.K. voted to leave the European Union. Only thing is that federal law is pretty clear that soliciting donations from foreign nationals is illegal.

“This is an open and shut case of the Trump campaign illegally soliciting foreign contributions,” said Democracy 21 President Fred Wertheimer in a statement. “It is striking and inexplicable that these solicitations brazenly continued after the Trump campaign was informed they were prohibited by law. As apparent knowing and willful violations of the law, the foreign money solicitations by the Trump campaign raise the issue of criminal conduct and require a Justice Department investigation.”

The letter contends that the Justice Department has the responsibility of enforcing campaign finance law against “knowing and willful” criminal violations of the law.

A July 16 article in The Hill found that Donald Trump was still soliciting donations despite the warnings.

Terri Butler, a member of Parliament told The Hill that she “was surprised to continue receiving fundraising solicitations from the presumptive GOP presidential nominee’s campaign at her official government email address.”

We reached out to the Trump campaign, but have not received an email back. We will update if we do.

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