Deputy Attorney General Rod Rosenstein told an interviewer he is satisfied with the work of special counsel Robert Mueller, whose investigation is being criticized by President Donald Trump as "the greatest Witch Hunt in U.S. political history."

The interview was posted Wednesday by NBC's Washington affiliate. Rosenstein, who wrote the memo that was the basis for Trump's firing of James Comey as FBI director, is overseeing Mueller's probe of Russian meddling in the 2016 presidential election.



Asked during the interview with NBC4 Washington whether he was satisfied with Mueller's probe, Rosenstein said "yes" but declined to offer more details.

"We don't talk about criminal investigations while they're ongoing, so what the American people will see is only if and when a case is charged," he said. "And there have been several cases charged to date."

The special counsel's office has charged four Trump associates with criminal wrongdoing since Rosenstein appointed Mueller in May. Two have pleaded guilty.

One of Mueller's lead investigators was reassigned for reportedly sending anti-Trump text messages.

White House press secretary Sarah Sanders has called for an investigation into the matter.

The special counsel's office operates with a degree of autonomy within the Justice Department, but reports to Rosenstein regarding its budget and "certain other matters," Rosenstein said.

Rosenstein is overseeing the probe because Attorney General Jeff Sessions, who was a Trump campaign surrogate, recused himself in March.

A must watch: Legal Scholar Alan Dershowitz was just on @foxandfriends talking of what is going on with respect to the greatest Witch Hunt in U.S. political history. Enjoy!

The deputy attorney general, who has served for Republicans and Democrats, was appointed by Trump in January and confirmed by the Senate in April.

Click here to watch the whole interview.