Washington (CNN) The likely incoming chairman of the House Judiciary Committee said Sunday that the first witness the panel will call next year will be acting Attorney General Matt Whitaker to question him about his "hostility" toward the Russian investigation.

"Our very first witness after January 3, we will subpoena, or we will summon, if necessary subpoena, Mr. Whitaker," New York Democratic Rep. Jerry Nadler told CNN's Jake Tapper on "State of the Union."

Whitaker, who was appointed last week by President Donald Trump after the President fired former Attorney General Jeff Sessions, has come under attack by Democrats for his public criticisms of the Mueller investigation.

"Well, the questions we will ask him will be about his expressed hostility to the investigation," Nadler said. "How he can possibly supervise it when he's expressed, when he's come out and said that the investigation is invalid."

Whitaker, formerly Sessions' chief of staff, called Mueller's appointment "ridiculous" and "a little fishy" on a radio show in 2017 before his appointment to the Justice Department. In a CNN op-ed written last year , Whitaker also argued that Mueller is "dangerously close to crossing" a red line following reports that Mueller was looking into Trump's finances.

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