Special counsel Robert Mueller's investigation into Russian collusion is not biased, insists former Clinton adviser Dave Kendall. The only people saying it is, are Fox News and those fools on the House Freedom Caucus, he wrote in a new Washington Post op-ed.

"This is true only on Fox News, in President Trump’s tweets and in the shoe pounding of the Freedom Caucus at legislative hearings," Kendall said.

In the piece, entitled, "Leave Robert Mueller Alone," Kendall charged that Trump supporters were trying to undermine the Mueller probe. Yet, it needs to go full speed ahead in order to protect our elections.

"It should be left to finish the work it has so ably begun: investigating thoroughly, prosecuting when the evidence justifies it and closing up shop silently — without harshly criticizing those not charged — when prosecution is not warranted," he wrote.

President Trump has dismissed the Russia probe as a "witch hunt" that has thus far resulted in absolutely no evidence that his campaign colluded with the Kremlin to win the 2016 election. But, he promised the press he would not fire Mueller.

Trump and his associates have reasons to suspect the special counsel probe. Recent reports revealed that FBI agent Peter Strzok had texted his mistress last year some seething anti-Trump, pro-Hillary Clinton messages. He was also found to have softened former FBI Director James Comey's critique of Clinton's email use as secretary of state.

Kendall explains Strzok's behavior by writing even FBI agents are entitled to have political leanings as long as it doesn't disrupt their work. Furthermore, he notes, leading officials at the Justice Department have contributed heavily to Republican candidates.

Strzok was removed from the Russia investigation, but Congress grilled FBI Director Christopher Wray and Deputy Attorney General Rod Rosenstein about how the controversy had affected the agency's integrity. Can the FBI still be trusted?

A group of Republican lawmakers are trying to find those answers by investigating the investigators.