President Trump 'wants to take down' special counsel Mueller: Top House Democrat “The president wants to take down Bob Mueller," Schiff said.

 -- The top Democrat on the House Intelligence Committee said President Trump wants to "take down" special counsel Robert Mueller who is conducting the investigation of Russian interference in the 2016 election and possible ties to Trump associates.

“The president wants to take down Bob Mueller. His lawyer wants to take down Bob Mueller," Rep. Adam Schiff, D-Calif., told ABC News' "This Week" co-anchor Martha Raddatz in an exclusive interview Sunday.

"The question is why," Schiff continued. “I think the answer is they want to lay the foundation to discredit whatever Bob Mueller comes up with. They’re essentially engaging in a scorched-earth litigation strategy that is beginning with trying to discredit the prosecutor.”

Schiff was responding to a question from Raddatz on whether Trump’s defenders are right to raise concerns that lawyers hired by Mueller have contributed to Democratic political candidates.

“Anyone who knows Bob Mueller knows he is choosing the best people to serve on this investigative team -- people that have experience in the issues that he wants to investigate and believes need to be investigated,” Schiff said.

President Trump has repeatedly expressed frustration with the Russia investigation, including saying on Twitter on Thursday that the probe is “the single greatest WITCH HUNT in American political history - led by some very bad and conflicted people!”

Raddatz also asked Schiff whether he believed Deputy Attorney General Rod Rosenstein should recuse himself from overseeing the special counsel investigation after Trump appeared on Friday to refer to Rosenstein in a tweet, which said, “I am being investigated for firing the FBI Director by the man who told me to fire the FBI Director! Witch Hunt”.

Rosenstein has privately discussed with colleagues the possibility of rescusal, as ABC News has reported.

Schiff said the deputy attorney general would not need to recuse himself unless Mueller concludes “that Rod Rosenstein’s conduct may be culpable in some way,” regarding the president’s firing of former FBI director James Comey. “I’m not saying this is the case … But if [Mueller] should conclude that …yes, Rod Rosenstein would need to recuse himself.”