Donald Trump predicted Friday in New Hampshire that Hillary Clinton could face federal perjury charges over sworn testimony she gave to Congress.

If true, that would compound legal problems that already include a newly revitalized probe of her classified email scandal and a year-long investigation into what Trump called a 'pay-for-play' link between Clinton Foundation donors and actions she took as secretary of state.

'Hillary Clinton lied to Congress under oath when she said she turned over all of her work-related emails, and that she didn't send classified information on her illegal server,' Trump told a cheering crowd in a Boston bedroom community near the state border.

'Meaning she may now face major problems for perjury.'

Donald Trump said Friday in New Hampshire that Hillary Clinton could face perjury charges for lying to Congress about her behavior linked to a lengthy classified email scandal

Clinton and Trump are running neck-and-neck in the Granite State, with every electoral vote likely to count toward a razor-thin victory for one of the in Tuesday's election

In light of a trove of 650,000 emails recovered from a laptop belonging to Anthony Weiner, a top aide's estranged husband – including some that law enforcement sources say are linked to Clinton – Trump questioned Hillary's public claim that she had deleted only emails that were unconnected with the State Department.

'The 650,000 emails include brand new emails not previously seen by authorities,' he said. 'She said she gave them all in, right? She said, "gave them all in".'

'Well, when we saw 650,000 we figured, "I guess there has to be some surprises." Wait 'til you see what they find in those 650, too. It won't be pretty.'

Trump scolded his Democratic rival for running her electronic communications under a veil of secrecy during the four years she was America's top diplomat.

'What a mess. And all she had to do is follow the rules, and assume people are watching or listening,' he said, referring to omnipresent hackers.

He contended that Clinton created her own political peril 'over what should have been nothing.'

'She'll be under investigation for years,' he predicted.

Trump said in the New Hampshire town of Atkinson that Clinton 'will be under investigation for years,' and the country can't handle the 'constitutional crisis' that would result if she were president

Trump's fans were out in their finery on Friday, chanting 'Lock her up!' at the mention of Clinton's name

Trump laid out a scenario in which a congressional civil investigation concurrent with a criminal FBI investigation could put pressure on a Hillary Clinton White House that the U.S. Constitution wasn't designed to withstand.

'If she were to win, it would create an unprecedented constitutional crisis. What a mess!' he said.

'I mean, we went through it with him,' Trump fumed, referring to Bill Clinton, 'with the impeachment and the lies. Aren't we tired of this stuff?'

Trump's warmup speakers were also heavy on mocking the former president as they entertained an audience that the local fire marshal cut off at just under 900.

Former U.S. Sen. Bob Smith launched into an impression of a sex-obsessed Bill Clinton, drawling: 'You know, if she goes to jail, I'm gonna be free as a bird to do what I wanna do!'

And former New Hampshire Gov. John Sununu, whose son Chris is running for the office he once held, pushed the bounds of New England's normally understated rhetoric.

'Do you think that Bill was referring to Hillary when he said: "I did not have sex with that woman?"' he asked, drawing a mixture of laughter and shouts of surprise at the reference to Monica Lewinsky, the White House intern whose affair with Clinton nearly cost him the presidency.

Sununu pointed to Smith and joked: 'He put me up to it.'

Moments earlier the former governor upbraided a man who yelled 'Execute her!' while the rest of the audience was chanting 'Lock her up!' – an anti-Hillary chant that has become part of the standard Trump rally repertoire.

'There's a limit to what's acceptable,' Sununu told him.

Smith addressed the concerns of some 'Never Trump' Republicans, and urged them to 'get over it' and come home to the GOP.

He quoted a Willie Nelson lyric that reads: I find it easy to forgive you, but forgetting seems to take a long, long time.'