Hillary ClintonHillary Diane Rodham ClintonGOP political operatives indicted over illegal campaign contribution from Russian national in 2016 Clinton lawyer's indictment reveals 'bag of tricks' Attorney charged in Durham investigation pleads not guilty MORE ally David Brock on Wednesday pressed his gambit to trade Donald Trump's tax returns for a $5 million donation from an anonymous longtime Republican to a veterans charity.
Brock said on a call with reporters that he has "documentation that the funds are being held in a bank account for this purpose." If Trump, the presumptive GOP presidential nominee, makes nine years of his returns public this week, ahead of the Republican National Convention in Cleveland, the donor will contribute money to a veterans charity of Trump's choosing.
"The goal of our challenge is to find out what Trump is hiding," Brock said. "Trump's tax returns would provide hard information on how successful his businesses really are, how much income he earns and from what sources, how he's managed his tax burden and to what extent he's been a philanthropist."
Brock described the donor as a "lifelong Republican" who has supported GOP presidential tickets for decades. The donor was also described as an "active philanthropist" and "political giver," but Brock would not say where the donor lived or in what industry he worked.
For the donor, Trump releasing his returns is "a matter of character," Brock said, noting that other Republicans such as 2012 GOP presidential nominee Mitt Romney have also called on Trump to release his returns.
Trump has said he won't release his tax returns until the Internal Revenue Service (IRS) finishes an audit, though the IRS has said that nothing prevents people from releasing their own tax information. Trump has also said his returns are "none of your business."
"We believe that Trump's tax returns are the voters' business," Brock said. "This is a case of what we don't know will hurt us."
Clinton, the presumptive Democratic presidential nominee, has released more than 30 years of her returns.
A spokeswoman for Trump did not immediately respond to a request for comment on the challenge.