In the run-up to Supreme Court Justice Brett Kavanaugh’s confirmation hearing, the FBI was tasked with conducting a thorough background investigation. Specifically, they were supposed to look into the multiple allegations of sexual misconduct leveled against Kavanaugh. After the investigation was completed, several Republican lawmakers used it as the basis for their decision to vote to confirm Kavanaugh, including the previously undecided Sen. Jeff Flake of Arizona. Sen. Mitch McConnell of Kentucky, the majority leader, implied that the report exonerated Kavanaugh completely. But now, a new book suggests the probe may have been less than thorough.

If accurate, this would represent a big mistake on the part of the FBI. Without the truth, a cloud will hang over Kavanaugh’s head and an asterisk will accompany his decisions. The only way to repair the damage is for Congress to pick up where the FBI left off.

Without the truth, a cloud will hang over Kavanaugh’s head and an asterisk will accompany his decisions. The only way to repair the damage is for Congress to pick up where the FBI left off.

Kavanaugh had appeared to be destined for confirmation in 2018 when multiple allegations surfaced that he had engaged in sexual misconduct as a high school and college student in the 1980s. Christine Blasey Ford, a California professor, testified before the Senate Judiciary Committee that during high school, a drunken Kavanaugh dragged her into a bedroom at a house party, threw her onto a bed, pinned her with his body and groped her. Then came another allegation by Deborah Ramirez, a former classmate at Yale who alleged that during a dorm party in college, Kavanaugh pulled down his pants and thrust his penis in her face. (Kavanaugh denied both Ford and Ramirez’s allegations under oath.)

As a result of these allegations, Flake and fellow Republican Sen. Susan Collins of Maine demanded a delay in the confirmation vote to give the FBI time to conduct a supplemental investigation. The FBI was given one week by President Donald Trump to complete its work. The senators reviewed the FBI’s report, and voted to confirm Kavanaugh, 50-48, including both Collins and Flake.

In recent days, new reporting indicates that during the supplemental investigation, Sen. Christopher Coons, D-Del., a member of the Senate Judiciary Committee, relayed to the FBI yet another allegation of sexual misconduct against Kavanaugh. Reports indicate that this allegation was made by Max Stier, a Yale classmate of Kavanaugh’s. Stier is now a prominent lawyer who surely understands the stakes having previously served as a law clerk to Supreme Court Justice David Souter.

According to a New York Times essay published on Sunday, based on a new book by Times reporters Robin Pogrebin and Kate Kelly, Stier has alleged that during another college party, Kavanaugh pulled down his pants and Kavanaugh’s friends forced his penis into the hand of a female student — not Deborah Ramirez. The Times was criticized for omitting from its article the fact that the female student declined to be interviewed by the book’s authors and did not recall the incident.

But even if the student does not remember the incident, others who witnessed it could have been interviewed. And yet, the FBI reportedly did not interview Stier or other witnesses to this event, even though a members of the Senate Judiciary Committee requested it. Nor did the FBI interview the 50 witnesses whose names the lawyers for Ford and Ramirez sent to them. The FBI instead limited its investigation to interviewing nine witnesses over six days. The artificial time limit was completely unnecessary for investigating the qualifications of someone seeking a lifetime appointment.

Some may argue (and in fact, already have argued) that the incidents were too old, occurring at a time when Kavanaugh was too young for them to matter today. But it is clear that the senators who were casting deciding votes thought these incidents mattered when they asked for the supplemental background investigation.

For those who wanted more evidence before disqualifying Kavanaugh than the compelling testimony of Ford, the additional incidents matter. Federal prosecutors often prosecute serial bank robberies together rather than deferring to separate local prosecutors to try the cases individually so that evidence of all of the robberies can be presented to the same jury. This is because in addition to achieving efficiency, the grouping also permits a jury to understand the full scope of bad behavior. At some point, the multiple allegations also become cross-corroborating — maybe someone can be falsely accused of committing one crime, but who gets falsely accused of committing three crimes that are eerily similar in their modus operandi?

Similarly, with Kavanaugh, the multiple allegations are sufficiently similar to lead one to believe that it is at least worth investigating whether Kavanaugh has abused and demeaned women, and, perhaps, is therefore unqualified to sit on the highest court in the land.

The FBI’s failure to fully investigate Kavanagh’s background raises important questions. Why was the investigation truncated? Did Collins, Flake and other senators know? Did the FBI just do a sham investigation on its own? Is it possible someone in the Trump administration directed or suggested that the FBI should limit its investigation?

And more important, what is the remedy for this investigative failure? Congress should do now what the FBI should have done in the first place and interview all witnesses to all incidents. Only upon reviewing all of the evidence can a rational conclusion be drawn. If the evidence shows that Kavanaugh committed perjury during his testimony, he could be impeached for procuring his position by fraud.

And the public must learn the lesson that we should take seriously accusations of sexual misconduct and thoroughly investigate them before putting people in positions of power.