GOFFSTOWN, N.H. — The day after he released a decade of his own tax returns, Democratic Vice Presidential candidate Sen. Tim Kaine lambasted Republican nominee Donald Trump for not releasing his.

"Even Richard Nixon released his tax returns to the public when he was running for president," Kaine told a campaign rally in New Hampshire Saturday.

Nixon didn't actually release his returns while campaigning: he released them while under audit in 1973.

Trump is undergoing an audit — which his campaign says is why the candidate has not yet released his tax returns. The campaign says the returns will be released once the audit is completed.

Kaine on Saturday questioned whether there could be shockers in Trump’s finances and whether Trump’s investments might show connections with "people we have some questions about." He also wondered whether the Republican nominee would stand to benefit from his own tax plan, and if Trump donated as much to charity as he has claimed.

"We might find that this generosity that he's claiming is just smoke and mirrors," Kaine told the crowd. "I think that's probably the case."

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Related: Clinton, Kaine Release Tax Records

"My wife and I put out 10 years of tax returns yesterday, right 10 years," he said. "You have a right to know. I don't care whether you are a Democrat, Republican or independent, you have a right to know."

Kaine again also accused Trump of not being a supporter of the military by tying the issue to how much Trump might pay in taxes.

"He's bragged about using every trick and artifice he can to pay no taxes," Kaine said. "Why does that matter? Well, let's just focus on this one for a minute. Donald Trump says he's gonna be a great Commander-in-Chief for the military. Who supports the military? I mean, we pay taxes to support the military ... If you haven't been supporting the military during your entire, during your entire life, don't tell me you'll suddenly start if you get to be Commander-in-Chief. I don't believe that for a minute, I don't believe it for a minute."

Just released my tax returns, @realDonaldTrump. Where are yours? https://t.co/PgQ6XIGTqg — Senator Tim Kaine (@timkaine) August 12, 2016

Kaine was speaking in front of capacity crowd at Saint Anselm College, just outside of Manchester. There were 667 people in attendance, and the fire marshal had to close the entrances, the campaign said.

Kaine also brought up Trump’s claim from months ago that Sen. Ted Cruz’s father was "palling around with Lee Harvey Oswald" and that President Barack Obama was the "founder of ISIS."

"This guy will make up anything!" Kaine said.

Related: Trump's Theories Aren't Outside GOP Mainstream

This was Kaine's first campaign rally in the Granite State since Clinton picked him as her running mate three weeks ago, and he predicted that he would be back "a lot because New Hampshire is very, very important."

Earlier Saturday, an aide said that Kaine spoke with Diane and John Foley, the parents of journalist James Foley, a New Hampshire native who was abducted by ISIS in 2012 and killed by the terror group two years later.

Kaine ran into the couple as he was leaving the Radisson Hotel in Manchester, and the meeting was apparently unplanned. It was not an endorsement, but the aide said the couple wanted to speak with Kaine about the James W. Foley Legacy Foundation.

The couple has has been very critical of the Obama administration’s policy on hostages, and Diane Foley told CNN in September 2014 that she was "embarrassed and appalled" by the U.S. government and said more could have been done to rescue her son.

In the fall of that year, the Foleys also met Trump when he was the featured speaker at a New Hampshire banquet where the couple accepted a posthumous award on behalf of their son. That’s where Trump gave them a $25,000 check made out to the James W. Foley Legacy Fund, the New Hampshire Union Leader reported.

Kaine’s New Hampshire swing lasted two days, and he also greeted guests at a number of local businesses in Concord and Manchester on his trip. Kaine resumes the campaign trail next week when he heads to North Carolina and Iowa.