Story highlights "He's always looking for a mark, some victim for one of his schemes," Reid said

The Nevada Democrat has repeatedly attacked Trump this campaign

Washington (CNN) Senate Minority Leader Harry Reid offered an explanation Tuesday for why Donald Trump won't disclose his tax returns: the Republican presidential nominee is "faking his net worth."

The Nevada Democrat -- and frequent Trump foe -- levied the charge on Twitter, evoking a similar claim he made against the GOP's 2012 nominee, Mitt Romney.

"Trump is faking his net worth. He's not as rich as he would have us believe + a bad businessman. That's why we can't see his tax returns," Reid tweeted.

Trump is faking his net worth. He's not as rich as he would have us believe + a bad businessman. That's why we can't see his tax returns. — Senator Harry Reid (@SenatorReid) September 20, 2016

Reid, citing an unnamed source, memorably accused Romney during the 2012 race of going 10 years without paying federal income taxes. Romney released a 20-year summary of his tax liabilities from 1990 through 2009, and his tax returns from 2010 and 2011. But he did not release additional returns.

The Trump campaign did not return CNN's request for comment.

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