'Frankly, I think we have good reason to believe that there's a bombshell in Donald Trump's taxes.'

In an interview with Fox News’ Neil Cavuto, former Massachusetts Gov. Mitt Romney hinted on Wednesday there may be a “bombshell” in Donald Trump’s tax information.

“Frankly, I think we have good reason to believe that there’s a bombshell in Donald Trump’s taxes,” he said.

Romney has stepped up his troll game by poking fun at Trump’s thin-skinned reaction.

Methinks the Donald doth protest too much. Show voters your back taxes, @realDonaldTrump. #WhatIsHeHiding — Mitt Romney (@MittRomney) February 25, 2016

When asked what could be hidden in Trump’s finances, Romney suggested the real estate mogul may not be as rich as he claims or may not be the biggest advocate for veterans and the disabled if the information shows he doesn’t put his money where his mouth is.

“Donald Trump has said he’s the best in the country for the disabled veterans and for the disabled generally,” Romney said. “Well, if his taxes show that he hasn’t made any contributions to the disabled veterans, or to the disabled generally, that would be a big issue.”

Romney himself was very publicly criticized for his finances when he ran (unsuccessfully) for president in 2012. Even after he turned over a whopping 550 pages of tax returns to the public, he was still excoriated. This time around, Romney has been advocating that his Republican colleagues undergo the same type of financial scrutiny.

Trump likes to talk about his wealth and remind voters how rich he is. He is also reportedly very sensitive about his finances. In 2013, comedian Anthony Jeselnik told Joan Rivers that when he roasted Trump on Comedy Central, the only thing off limits were jokes suggesting Trump had less money than he claims.

(h/t The Daily Beast)