Transcript for Donald Trump Continues His Message of a 'Rigged' Election System
The task for Donald Trump's campaign tonight, to keep him on-message, and to keep the focus on these new headlines involving Hillary Clinton. But he still needs a sweep of many of the battlegrounds on election night, and some blue states, as well. Which explains why he's in Michigan tonight. ABC's Tom llamas is there, too. Reporter: Tonight, Donald Trump riding a wave of momentum. The renewed investigation into Hillary Clinton's e-mail server shifting the tide. The Clinton crime spree ends on November 8th, it's going to end on November 8th. Reporter: Trump even gloefting over the redrent developments. Thank you, Anthony Weiner. Reporter: Trump supporters here in Michigan tell us there is a renewed enthusiasm within the trump campaign since the news broke of that new FBI inquiry. Absolutely, they're totally energized. Now, the rest of the country is finding out what we already understood, she's a criminal, and she can't be allowed to move back into the oval office. Reporter: For months, trump slammed the FBI, even safing this just hours before director Comey upended the race on Friday. But the system is rigged. I think the biggest rigging of all is what's happened with the FBI and the justice department with respect to Hillary Clinton. Reporter: But now trump heaping praise on the FBI director. It took a lot of guts. But I'll tell you what, what he did, he brought back his reputation. Reporter: In these crucial final days, trump amplifying his prediction of widespread voter fraud. This time, questioning mail-in ballots. Like people say, oh, here is a ballot, here is another ballot, throw it away. Oh heeshgs's one I like, we'll keep that one. I have real problems, so, get your ballots in. Reporter: Over the weekend, word of an arrest for voter fraud. A woman in Iowa who allegedly tried to vote twice. Turns out she's a trump supporter. She told Iowa public radio she worried her first ballot would be tampered with. "The polls are rigged," she said. And Tom llamas with us tonight from Michigan. And Tom, more than 23 million Americans have already voted, election day a week from tomorrow. And it is very clear from the trump campaign that they sense an opening here with these new headlines about Hillary Clinton and the e-mails. Reporter: David, the sense out here on the campaign trail is that it's the fourth quarter and Donald Trump feels like he has the ball back. He's going to continue to hammer this e-mail issue for the next seven days to remind voters in his opinion that Hillary Clinton can't be trusted. David?
This transcript has been automatically generated and may not be 100% accurate.