A senior campaign aide to Donald Trump stunned CNN's Kate Bolduan on Friday by suggesting in an interview that Hillary Clinton wouldn't tell the truth about her private email server even if she were waterboarded.

"You couldn't get the truth from Hillary Clinton if you waterboarded her," Barry Bennett, who previously served as Ben Carson's campaign manager, told Bolduan while the two were discussing Clinton's email scandal.

"What?" Bolduan responded incredulously.

"You couldn't get the truth out of her with a waterboard," Bennett repeated.

Shortly before that exchange, Bennett told Bolduan that Clinton's use of an unsecure email server during her tenure as secretary of state was a "real problem," and criticized her for declining to be interviewed by the State Department's Office of the Inspector General.

"I mean, it's crazy. I mean, she has continued to lie about it, right? She told us the lawyers signed off on it, the inspector general said that's not true. She said she would cooperate with all of the investigations, she stonewalled the [State Department OIG] and now everybody's taking the Fifth," he said.

Bennett added that if U.S. Attorney General Loretta Lynch "tries to block" an indictment of Clinton, "special counsel should be appointed."