Former Special Counsel Robert Mueller refused to confirm that he interviewed Christopher Steele, a former British intelligence operative who authored the now-debunked dossier alleging collusion between President Donald Trump and Russia, during his 22-month investigation into election interference.

While testifying in front of the House Judiciary Committee on Wednesday, Mueller was questioned by Rep. Greg Steube (R-FL) regarding his two-year, $25.2 million investigation into Russia’s meddling during the 2016 presidential election.

Steube, a freshman from Florida, was particularly interested in knowing how the 74-year-old former special counsel handled the Steele Dossier, a topic Mueller said he would refrain from discussing in his opening statement. The congressman noted that despite Mueller’s decision to stay silent, the final report released by the special counsel’s office mentions Steele’s “unverified allegations” numerous times.

“How long did it take you to reach the conclusion that it was unverified,” Steube asked as Mueller again refused to engage on the topic. “It’s actually in your report, multiple times as ‘unverified’ and you’re telling me you’re not willing to tell us how you came to the conclusion that it was unverified.”

Steube then asked if Mueller or his team had interviewed Steele, a question the former special counsel also refused to answer.

“You can’t tell this committee as to whether or not you interviewed Christopher Steele in a 22-month investigation with 18-lawyers,” Steube said.

Mueller claimed he could not answer the question because it pertained to an investigation “being handled by others in the Department of Justice.”

“But you’re here testifying about this investigation today,” Steube said. “And I am asking you directly did any members of your team or did you interview Christopher Steele in the course of your investigation?”

.@RepGregSteube: Given your 22 months of investigation, millions of dollars spent and millions of documents, did you find that any American changed their vote because of Russian interference?#Mueller: That was outside our purview. Oh? pic.twitter.com/Xx7gqmJNnf — Nick Short 🇺🇸 (@PoliticalShort) July 24, 2019

Steele, a British citizen, in many ways is at the center of the collusion hoax. In 2016, the former Mi6 operative was hired by the opposition research firm Fusion GPS to dig up dirt on then-candidate Donald Trump. The clients who had contracted with Fusion GPS and bankrolling the endeavor were none other than attorneys working for the Democratic National Committee and Hillary Clinton’s presidential campaign.

Steele’s dossier on Trump, which has largely been debunked, was partially the basis for the FBI to obtain a Foreign Intelligence Surveillance Act (FISA) warrant on members of the Trump campaign, including then-foreign policy advisor Carter Page. FBI officials failed to disclose to the FISA court that the dossier was funded by the Clinton campaign and DNC, though they did indicate the documents emerged from a opposition firm.

Since the history of the dossier has come to light, Steele has proved elusive to U.S. authorities. In May, he initially refused to meet with with officials from the DOJ tasked with investigating the the decision by FBI and Obama administration officials to spy on the Trump campaign. After his refusal became public, Steele agreed to cooperate with authorities and a subsequent interview was arranged in London.