Sam Clovis, President Trump’s pick for the U.S. Department of Agriculture’s (USDA) chief scientist, withdrew his name for consideration Thursday. Clovis is entangled in the ongoing investigations into possible Russian collusion in the 2016 election.

Clovis was reportedly questioned by Special Counsel Robert Mueller’s team of investigators last week, according to NBC News. Clovis has ties to a former Trump campaign aide who already pleaded guilty to lying to the FBI about his own Russian connections.

In a letter to Trump, Clovis said he does “not want to be a distraction or a negative influence.” He also mentioned “relentless assaults on you and your team” that "seem to be a blood sport."

Who is Sam Clovis?

Clovis, 68, has a full resume. He is a former Air Force officer, college professor, conservative radio host and defense contractor.

From Iowa, Clovis unsuccessfully ran for Senate in his state in 2014, earning the endorsement of former Republican presidential candidate Rick Santorum. While a candidate, Clovis said then-President Obama’s race saved him from impeachment.

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Clovis was a business and economics professor at Morning Side College in Iowa. He attended the Air Force School in Colorado Springs, earned an MBA from Golden Gate University in California, studied national security at Georgetown University and earned a doctorate in public administration from the University of Alabama, according to the Omaha World-Herald.

How is Clovis connected to Trump?

Clovis was Trump’s pick to be the USDA’s chief scientist – and he was a former policy adviser and co-chair for Trump’s presidential campaign.

Clovis was responsible for releasing the names of Trump’s foreign policy advisers in March, which included George Papadopoulos. Papadopoulos pleaded guilty in October to lying to the FBI about his Russian contacts and efforts to set up meetings between Russian officials and members of the Trump campaign.

Clovis’ lawyer confirmed that he brought Papadopoulos onto the campaign, according to the Associated Press.

In court papers, an unnamed supervisor – who Clovis’ lawyer confirmed was Clovis – was said to have received some of Papadopoulos' email exchanges about his attempts to line up a meeting with the Russians, appearing to encourage the effort at one point by responding "Great work." He also later encouraged Papadopoulos to travel to Russia on his own.

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However, the lawyer said Clovis opposed any trip to Russia for Trump’s campaign, including Trump.

Sen. Pat Roberts, R-Kan., said that Clovis is “a fully cooperative witness” in the Senate’s probe into potential Russian collusion, Politico reported.

Clovis was expected to face a tough confirmation hearing in the Senate later this month. He withdrew his nomination Thursday as he said he did “not want to be a distraction or a negative influence,” in a letter to Trump.

Fox News' Kaitlyn Schallhorn and The Associated Press contributed to this report.