U.S. Sen. Robert Menendez described the latest FBI investigation of Judge Brett Kavanaugh as "bullshit."

"If that's an investigation, it's a bullshit investigation," Menendez, D-N.J., tweeted out Thursday.

Just read the FBI report on Kavanaugh - if that’s an investigation, it’s a bullshit investigation. pic.twitter.com/9D8oeVMEoU — Senator Bob Menendez (@SenatorMenendez) October 4, 2018

Menendez, an early opponent of Kavanaugh's nomination, was one of several Democrats, including U.S. Sen. Cory Booker, D-N.J. and the party's Senate Judiciary Committee members, who said the FBI refused to interview several witnesses who said they would come forward with information that would support the allegations against the U.S. Supreme Court nominee.

Senate Republicans, who had postponed a vote on Kavanaugh's confirmation after U.S. Sen. Jeff Flake, R-Ariz., insisted on a new probe, plan a preliminary vote on Friday and proclaimed that the FBI investigation turned up no collaborating evidence.

Democrats said that was because the White House and the GOP Senate refused to allow the FBI to look for any.

"The reality is, that is not a full and thorough investigation," Menendez said in the video posted to Twitter. "Evidently, the Republicans who gave the direction to the FBI of what could be investigated was extremely limited.

"I hear a lot about lack of corroboration. Well, you don't get corroboration if you don't talk to corroborating witnesses at the end of the day, and obviously that didn't happen here," he continued. "And so, I'm amazed. I'm amazed that for the highest court in the land this is the type of report the FBI produces."

Menendez was just the latest Democrat to slam the investigation. Earlier Thursday, Sen. Cory Booker, D-N.J., called on his 4.1 million Twitter followers to call their senators.

A research psychologist, Christine Blasey Ford, testified that Kavanaugh sexually assaulted her while both were in high school. Kavanaugh denied the allegations. The FBI didn't interview either of them in its latest probe.

On the Senate floor Thursday, Senate Majority Leader Mitch McConnell, R-Ky., confirmed that the first vote on Kavanaugh's nomination will take place on Friday.

Jonathan D. Salant may be reached at jsalant@njadvancemedia.com. Follow him on Twitter @JDSalant or on Facebook. Find NJ.com Politics on Facebook.