All eyes will be on axed FBI Director James Comey Thursday as he testifies before the Senate Intelligence Committee – but also in the spotlight will be the 15 senators who will grill him.

The bipartisan panel is made up of eight Republicans and seven Democrats, and is led by Chairman Richard Burr (R-NC) and Vice Chairman Mark Warner (D-Va.).

Warner, who’s been outspoken about Trump’s criticism of Comey during his Oval Office meeting with Russian officials last month, is expected to be the more vocal of the pair.

Burr has questioned the “timing and reasoning” behind Comey’s firing. He has said he wants the committee to get to the bottom of whether President Trump had any involvement with Russia.

“We know that our challenge is to answer that question for the American people,” he said in March, according to the Washington Post.

Warner added, “We’re going to get it right.”

The congressional hearing is expected to last about three hours.

Here are four other key senators:

James Lankford (R-Okla.)

Lankford, 49, a conservative, is serving his first term in the Senate after spending four years in the House. He’s shown general support for Trump but also called on him to release his tax returns.

He’s hoping for an open discussion with Comey.

“I would hope he could talk through what happened around his firing, the memos that he wrote, the nature of his memos, the reason that he put those memos out there, but also the core issues that we’re still dealing with on the Russia investigation itself,” Lankford said. “There are still a lot of unanswered issues that we have to be able to get resolved.”

Susan Collins (R-Maine)

Collins hasn’t been shy about voicing criticism toward Trump, whom she didn’t support for president. The 64-year-old centrist also opposed some of his Cabinet nominees.

She was easily reelected to her fourth term in the Senate in 2014 and is considered a potential gubernatorial candidate.

Collins wants to hear directly from Comey about his interactions with Trump, who asked the ousted FBI head for “loyalty” to “lift the cloud” cast over his administration by the ongoing Russia probe.

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

Joe Manchin (D-WV)

The former West Virginia governor, who is in his second term in the Senate and is running for a third, is considered the most conservative Democrat in the Senate.

He’s been quick to praise the president and align himself with him.

Manchin, 69, asked his constituents to send in questions ahead of Comey’s Q&A and received over 600 responses, which will help shape the senator’s questioning.

He implored Comey to “just tell the truth. Tell the truth.”

Kamala Harris (D-Calif.)

Harris served as a former prosecutor, district attorney of San Francisco and California’s attorney general – so she’s used to asking tough questions. She’s a newcomer to the Senate after having been elected last year to replace Barbara Boxer, who retired.

On Wednesday, she was chided by Chairman Burr over her aggressive questioning of Deputy Attorney General Rod Rosenstein over the Russia probe.

Harris, 52, told reporters she’d been diligently preparing for Comey’s testimony.

“Reviewing everything that has happened in previous hearings, reviewing public source documents including a lot of the interviews that you all have accumulated and conversations that you all have had as press, reviewing the timeline and the calendar around some of the dates that we know certain conversations or hearings occurred and where there were certain answers to questions, and checking to make sure that they were consistent,” she said.

With Post Wires