Lt. Col. Alexander Vindman said it's "preposterous" to think he'd leak information.
"Colonel, you never leaked information?" Rep. Jim Jordan asked Vindman, who is under oath.
"I never did — never would. That is preposterous that I would do that," he said.
Just before this, Jordan asked Vindman about testimony from Tim Morrison, in which he said Vindman may have leaked information.
"Mr. Jordan, I would say that I can't say what Mr. Morrison — why Mr. Morrison questioned my judgment," Vindman said. "We had only recently started working together. He's — he wasn't there very long, and we were just trying to figure out our relationship."