Washington CNN  — 

President Donald Trump’s former personal lawyer and fixer Michael Cohen said under oath Wednesday that he had never traveled to Prague to collude with Russian officials in 2016, denying a key claim of the infamous “dossier” that alleged a conspiracy between Trump and the Kremlin.

His comments during a marathon House Oversight Committee hearing were his first public denial under oath, meaning he could be prosecuted for perjury if he was not telling the truth.

“I’ve never been to Prague. … I’ve never been to the Czech Republic,” Cohen told lawmakers.

Cohen has denied the allegation from the very beginning. CNN did not publish the unverified intelligence memos compiled by a retired British spy but was first to report in January 2017 that the documents were being circulated among US intelligence agencies.

The dossier said Cohen had traveled to Prague during summer 2016 and struck a corrupt bargain with Russians, agreeing to coordinate with their efforts to help Trump win the election.

And Trump has always insisted that there was “no collusion whatsoever” between his campaign and the Kremlin. At Wednesday’s hearing, Cohen said he didn’t know about “direct evidence” of collusion but “I have my suspicions,” and he accused Trump of lying about topics related to Russian election interference.

In private testimony to congressional committees in 2017, Cohen denied that he had gone to Prague. But in that same testimony, he lied to lawmakers about efforts to build a Trump Tower in Moscow. He pleaded guilty last year to lying to Congress and to eight unrelated charges of financial fraud and campaign finance violations. His three-year prison term begins in May.

Rumors about Cohen’s supposed Prague trip have flourished among Trump’s opponents and liberal-leaning Twitter personalities who follow the Russia investigation. The chatter flared up last year when a reputable news service reported that special counsel Robert Mueller had evidence linking Cohen to Prague. That report wasn’t corroborated by CNN or any other outlets.

Trump and Cohen are now bitter enemies. Trump has called his former lawyer a “rat” for helping federal investigators, and Cohen said Wednesday that Trump is a racist “conman” who broke the law. But back in 2017 when the allegations came out, Trump rushed to Cohen’s defense.

“Michael Cohen is a very talented lawyer, he’s a good lawyer in my firm,” Trump said after the dossier was published, adding that he had reviewed Cohen’s passport and didn’t see evidence of any Prague trip. “He wasn’t out of the country. … It turned out to be a different Michael Cohen. … It’s a disgrace and I think they ought to apologize to start with Michael Cohen.”

In addition to the speculation about Prague, some other key dossier claims remain unproven after two years of searching, including salacious allegations about Trump’s visit to Moscow in 2013.

But many of the allegations that form the bulk of the intelligence memos have held up over time or have proved to be at least partially true. This includes claims that Russian President Vladimir Putin oversaw a vast operation to interfere in the US election and that there were extensive contacts between Trump campaign associates and Russian officials during the campaign.