A new FBI investigation and a full day for senators to read it did nothing to clarify what might happen Friday in the partisan ruckus over Supreme Court nominee Brett Kavanaugh.

Senate Majority Leader Mitch McConnell and Republicans said they were trying to work out a mid-morning cloture vote on the nomination, but one was not officially announced when the Senate adjourned Thursday. The vote is expected to happen as early as 10:30 a.m. Friday.

But that was about the most certain aspect of the contentious vote, other than that the outcome would be close and more protests would erupt across the Capitol complex.

Four undecided senators gave the reporters hounding them around the Capitol no clues about how they would vote.

Watch: Massive, Loud and Passionate Anti-Kavanaugh Protest Takes Over Hart Building

Sen. Joe Manchin III of West Virginia, the only undecided Democrat, spent an hour Thursday afternoon reading the only copy of the supplemental FBI background investigation of Kavanaugh, located in a private room in the Capitol basement.

But Manchin, who is running for re-election in a state President Donald Trump handily won in the 2016 election, told reporters that he had to leave the room before he finished reading the report because it was the Republicans’ turn to check out the 46-page document — and he gave no hint about how he might vote.

“I gotta be honest, I’m going back tomorrow because I’ve got to finish, because they threw us out,” Manchin said. “I’m going through it, and I’ve got more that I’ve got to go tomorrow morning, and they’ll have it all ready so I can see it when I get in.”

Sen. Susan Collins, R-Maine, spent nearly two hours reading the investigation, and then spent a minute not responding to the questions that tried to tease out how she would vote.

“I have finished reviewing and reading all of the interviews but I am not giving comment now,” Collins said. “I have read all the interviews.”

Earlier Thursday, Republican Sens. Jeff Flake of Arizona and Lisa Murkowski of Alaska, who wanted the one-week FBI investigation before a floor vote, also said they were reading the investigation and didn’t tell reporters how they would vote.

Vice President Mike Pence will return to Washington on Saturday in case he needs to cast a tie-breaking vote, a White House official said.

Thursday afternoon, Capitol Police arrested 293 protesters in the atrium of the Hart Senate Office Building and charged them with “crowding, obstructing or incommoding.” There were nine additional arrests around 5:20 p.m. in the Dirksen building near Collins’ office. Those protesters face the same charges.

Other groups announced protests overnight or Friday morning.

If Kavanaugh’s nomination does survive Friday’s vote, a final confirmation vote is expected to happen Saturday.

But Sen. Steve Daines, R-Mont., said that he will attend his daughter’s wedding in Montana on Saturday regardless of a possible weekend vote on the embattled Supreme Court nominee.

— Patrick Kelley, Katherine Tully-McManus, Jennifer Shutt and John T. Bennett contributed to this report.