Fox News host Bret Baier reported Thursday that federal investigators are going to "push for an indictment" in their lengthy probe into pay-to-allegations surrounding Hillary Clinton's State Department and the Clinton Foundation.

Baier, updating remarks he made Wednesday about there being "likely an indictment" in the expansive federal probe, said investigators have confidence in the evidence coming in on the case.

"Do the investigators believe that they have evidence of pay-for-play? That's the main question here," America's Newsroom host Martha MacCallum said.

"Yeah, I think they believe that they have a lot of evidence, but as in any case, you have to build the evidence, and it continues to come in," Baier said. "You eventually have to get some people to sign on or cooperate and testify, so this is all building evidence to a case that has to be made by a prosecutor. And, that's why the jumping to likely indictment, they are going to continue to push for an indictment, and that's what I should have said, but there is a confidence of the evidence that's coming in on this case."

"Bottom line is, if anybody says the Clinton Foundation investigation is over, it's not," he added. "It is widespread. Four different FBI offices have taken part in it. It is aggressively being pursued."

Baier followed up on his previous night's reporting that the FBI has been "aggressively" investigating potential pay-to-play links between the Clinton Foundation and the State Department for more than a year. The investigation is reportedly "so expansive," Baier said, and they have re-interviewed many people. His sources said there was "a lot" of evidence and an "avalanche coming in every day."

Baier slightly altered widely reported remarks he made to Brit Hume on Wednesday that "barring some obstruction in some way, they believe they will continue to likely an indictment."

"I got to the end of that and said they have a lot of evidence that would likely lead to an indictment, but that's inartfully answered," he said. "That's not the process. That's not how you do it. You have to have a prosecutor. If they don't move forward with a prosecutor with the [Justice Department], there would be, I'm told, a very public call, for an independent prosecutor to move forward. There is confidence in the evidence but for me to phrase it like I did—of course that got picked up everywhere—but the process is different than that."

Baier also pushed back on claims from Clinton allies that many of the emails on Anthony Weiner's computer relating to Clinton's private email server are duplicates.

"They have found hits, new hits in the emails that they believe are new emails. In other words, not duplicates that were on Hillary Clinton's server," Baier said.