Yet another top investigator in Mueller's investigation is being accused of political bias (UPDATED)

Another lead investigator in special counsel Robert Mueller's investigation is being accused of political bias, the Wall Street Journal reported.

What's going on?

According to the Journal's report, Andrew Weissmann, who is leading the probe's Paul Manafort and Rick Gates cases, both attended Hillary Clinton's election night party at the Javits Center in New York City and praised Sally Yates' efforts to thwart President Donald Trump.

The revelations are significant because Weissmann is considered to be the most senior investigator in the probe second only to Mueller. The New York Times even described Weissmann as Mueller's "pit bull" and "lieutenant."

Weissmann's apparent political bias, along with the bias of FBI agent Peter Strzok — who was removed from Mueller's probe months ago for exchanging anti-Trump text messages with an FBI lawyer whom he was having an affair with — has many accusing the Trump-Russia probe of being politically motivated and biased.

Rep. Steve Chabot (R-Ohio), who sits on the House Judiciary Committee, called the "depths of this anti-Trump bias" on Mueller's team "absolutely shocking."

What are the details?

Judicial Watch obtained an email this week that revealed exactly what Weissmann wrote to then-Acting U.S. Attorney General Sally Yates on Jan. 30 after she instructed the Department of Justice not to defend Trump's controversial travel ban.

"I am so proud. And in awe. Thank you so much. All my deepest respect," Weissmann wrote. In the subject line of the email, he wrote: "I am so proud."

At the time Weissmann wrote the email, he was running the DOJ's fraud section, according to the Journal.

Weissmann has also given thousands of dollars to Democratic campaigns, including Barack Obama's 2008 campaign and the Democratic National Committee in 2006.

Should Weissmann step away?

According to Ari Fleischer, who was George W. Bush's press secretary, Weissmann should:

Is that it?

A third member of Mueller's team, Jeannie Rhee, has raised suspicions of political bias this week after it was reported she previously represented former top Obama adviser Ben Rhodes, according to Fox News.

Editor's note: This story originally reported that Andrew Weissmann is an FBI agent. However, that is incorrect. While Robert Mueller did appoint Weissmann to a management role in his Russia investigation, Weissmann officially works as the head of the criminal fraud section at the DOJ. To assume his role on Mueller's team, Weissmann had to take a leave from that post. Prior to that, he worked as a U.S. District attorney in New York, other various roles within the DOJ and in private practice at the New York law firm Jenner & Block.