Rudy Giuliani was reportedly warned he got 'untrustworthy' dirt on the Bidens

Rudy Giuliani apparently knew he shouldn't have gotten into this mess.

As the New York City mayor turned personal lawyer for President Trump searched for Ukraine-related dirt on the Bidens, former U.S. special envoy for Ukraine Kurt Volker reportedly says he warned Giuliani against it. Specifically, Volker said information Giuliani had received on former Vice President Joe Biden and his son Hunter Biden was "untrustworthy" and that his sources were "unreliable," two people familiar with Volker's Thursday testimony tell The Washington Post.

Volker resigned last week after he was named in a whistleblower complaint about Giuliani and Trump's dealings with Ukraine, but appeared on Capitol Hill on Thursday to testify for House investigators about the matter. The testimony was held behind closed doors, but the two sources say Volker "said he tried to caution Guiliani that his sources, including Ukraine’s former top prosecutor, were unreliable," per the Post. Volker also reportedly said he told Ukrainians to stay out of U.S. politics.

ABC News also reports that Volker shared text messages with Congress to other top American diplomats, which read "I think it's crazy to withhold security assistance for help with a political campaign." This is seemingly in response to how Trump appeared to imply he'd withhold aid from Ukraine in a July call with the country's president Volodymyr Zelensky unless Zelensky looked into the Bidens. Trump hasn't disputed he asked for the investigation, but insists there was no "quid pro quo" offered for the Biden dirt.