One of the issues that Sen. Susan Collins hopes to explore in a high-profile hearing Thursday with fired FBI chief James Comey is the honesty of President Donald Trump.

The Maine Republican told “Face the Nation” on Sunday she is eager to question Comey about the president’s “very interesting” assertion in his letter dismissing Comey that the former FBI director had informed Trump three times that he was not the subjection of an investigation.

“That phrase raises a lot of questions in my mind. Does Mr. Comey agree that that is what was said? Why would he tell the president that? What was the tone and the context of those discussions on three different occasions, if they, in fact, are accurately portrayed in this letter?” Collins said during the television broadcast.

Collins and U.S. Sen. Angus King, a Maine independent, are among 15 senators on the Senate Intelligence Committee who will get a chance to quiz Comey at a much-hyped hearing slated for Thursday morning.

They’ll get a warm-up session on Wednesday when Director of National Intelligence Dan Coats, Deputy Attorney General Rod Rosenstein, acting FBI Director Andrew McCabe and National Security Agency Director Mike Rogers are scheduled to talk to the committee about allegations that Russia interfered with last year’s presidential race in a bid to help Trump.

Comey said in March that the ongoing probe “includes investigating the nature of any links between individuals associated with the Trump campaign and the Russian government, and whether there was any coordination between the campaign and Russian efforts.”

During the earlier hearing, Comey said there had been no effort by the Department of Justice to block the investigation. But many news stories have asserted that Trump sought to shut down the probe.

Collins told “Face the Nation” host John Dickerson that “one of the reasons why it is so important for us to hear” from Comey is to sort out what actually transpired.

“The acting director of the FBI also said that there has not been an attempt to influence the investigation. And yet we hear about these memos to the file, all of these dinners and meetings between President Trump and the former FBI director. So, we need hear the directly from Mr. Comey on these important issues,” she said.

Collins cited the example of an alleged conversation that occurred between Trump and Comey shortly after the president fired his first national security advisor, Michael Flynn, who appears to be a central figure in the FBI probe.

She said that if the president told Comey “‘look, I just fired the guy, I feel bad for him, what do you think is going to happen,’ that is one thing. If, on the other hand, the president said to Mr. Comey, ‘I want you to end this investigation of General Flynn, I want it ended now, and if you don’t do so, you are going to be in trouble,’ that is a whole different nature of a conversation.”

“And that is why the tone, the exact words that were spoken and the context are so important. And that is what we lack right now. And we can only get that by talking to those directly involved,” Collins said. 

Collins said that is “very difficult to determine the facts of the Russian involvement in our elections last fall” with “so much speculation and so many stories and so many leaks” swirling around Washington.

“That is why the hearings this week are so important, particularly the hearing on Thursday with Mr. Comey,” she said.

“This will give us a chance to give his perspective on the issue of Russian involvement and also on the issue of collaboration or collusion. What has he seen? What initial judgments has he made?” Collins said.

The Senate panel has been looking into the issue since January with an accelerating pace. Collins said the committee has “a wonderful staff of experts in intelligence” but could use “an experienced investigator” to oversee their work.

King has also called for more help, including somebody with prosecutorial experience, to lend a hand to the probe.

Collins said the committee’s work is “taking up a great of time” in her schedule, including “three different trips” to the Central Intelligence Agency headquarters in northern Virginia “to over the raw intelligence” that undergirds the assertions made by government leaders.

“That is information we don’t usually get to see,” Collins said.