The FBI’s updated background investigation into Supreme Court nominee Judge Brett M. Kavanaugh reached out to 11 people, compiled 46 new pages of notes from its interviews — and appears to have made little headway in settling what really happened at high school and college parties more than 30 years ago.

The report had become the central focus of the debate over Judge Kavanaugh, with Democrats hoping it would corroborate allegations from Christine Blasey Ford and Deborah Ramirez, two women who say the judge groped or exposed himself to them during those parties.

Republicans, meanwhile, were convinced that the reports would back up the judge’s vehement denials, and they emerged more satisfied, saying the FBI found “no hint” of evidence to back up the women’s claims.

“I’ve learned nothing I didn’t already know,” said Sen. Lindsey Graham of South Carolina, who has emerged as the Republicans’ most powerful voice on the nomination.

Democrats suggested that they saw troubling details in the report but didn’t hint at what they were.

What they did say was that the FBI investigation left too many stones unturned for the Senate to be moving ahead with a vote.

“The most notable part of this report is what’s not in it,” said Sen. Dianne Feinstein, California Democrat.

She and other Democrats blamed the White House, speculating that the president’s aides issued orders preventing FBI agents from talking to certain people.

“Make no mistake, this investigation was rigged by the White House and Senate Republicans,” said Sen. Patrick J. Leahy, Vermont Democrat.

Republicans countered that the investigative decisions were left to the FBI.

“They were given the latitude they wanted. Nobody told them where to go, who to interview or how to interview them,” Mr. Graham said.

Details of the report — of which just a single copy exists at the Capitol — remain out of public view, locked in a room with access granted only to the 100 senators and fewer than a dozen staffers.

Interested senators were briefed by those staffers Thursday morning, with one hour dedicated to Democrats and the next to Republicans. Senators who wanted to read the reports went back throughout the day.

The 46 pages that the FBI compiled in its latest background investigation join some 1,500 pages amassed during six prior background checks, dating back to 1993, for the judge’s extensive service in the government.

With the new interviews, some 156 people have spoken to the FBI about Judge Kavanaugh over the years.

“The whole report, you could stand on it and paint the ceiling,” said Sen. John Kennedy, Louisiana Republican.

He said the investigation was thorough, and for the witnesses interviewed “it’s a cross between an endoscopy and a colonoscopy.” He said the interview with Mr. Judge, for example, lasted about three hours.

Of the 11 people the FBI contacted, senators said, 10 agreed to speak.

Six of the people the FBI contacted are known. They include Mark Judge, Leland Keyser and Patrick Smyth, the three people Ms. Blasey Ford has said she remembers at the party where she was assaulted.

Also interviewed was Tim Gaudette, who, according to Judge Kavanaugh’s calendars, hosted a party in July 1982 that Democrats say could have been the get-together where the assault happened, and Chris Garrett, a Kavanaugh friend who Ms. Blasey Ford says is the person who introduced her to Judge Kavanaugh.

The FBI also talked with Ms. Ramirez.

Three of the unnamed persons interviewed related to Ms. Ramirez’s allegations and one — a lawyer — was in relation to Ms. Blasey Ford’s accusations.

The final person of the 11 was an alleged eyewitness names by Ms. Ramirez, but that person declined to talk to the FBI, according to a summary released late Thursday by the Judiciary Committee.

But agents didn’t talk to Judge Kavanaugh, nor did they interview Ms. Blasey Ford.

Her attorneys said that decision should shame the FBI.

“The ‘investigation’ conducted over the past five days is a stain on the process, on the FBI and on our American ideal of justice,” the lawyers wrote.

They suggested eight witnesses whom the FBI should have talked to, including longtime friends of Ms. Blasey Ford, her husband, and the former FBI agent who conducted a polygraph exam in August. They also had said they would make available her therapist notes from 2012 and 2013, when she first publicly recalled the assault — but would turn them over only to the FBI, not the Judiciary Committee, which had requested them.

Ms. Ramirez’s attorney has suggested that 20 people might be able to back up her claim.

The FBI did not pursue any investigation into still other uncorroborated allegations lodged by others — including one by Julie Swetnick, who has given conflicting accounts but seems to suggest the judge was in the vicinity of high school parties where she says gang rapes happened.

While some Democrats have lent credence to her claims, most senators have avoided them.