Rep. Luis Gutierrez (D-IL) stormed out of a House Judiciary Committee hearing on immigration and border security on Thursday afternoon right after he accused Homeland Security Secretary Kirstjen Nielsen of being a liar.

After saying that “lying has become elevated to an astounding level of mendacity” in the Trump administration, Gutierrez, who will be retiring from Congress, said Nielsen’s tweet set the record for the biggest lie.

“But I have to say, the all time record for lying in the face of all the evidence was a tweet, you, madam secretary, sent out on June the 17th and says we do not have a policy of separating families at the border, period,” Gutierrez said. “That’s your Twitter account. That’s what you put out.”

Gutierrez also mocked Nielsen’s job security, addressing the numerous reports that have indicated that Trump is itching to replace her someone tougher.

“I suspect that if you still have your job, which seems to always be a big question, in three weeks, we’ll see if you still have the same sympathetic questions when you come back,” Gutierrez sneered.

Gutierrez then said it is “repugnant” and “astonishing” that the House majority during the Christmas season wears their “badge of Christianity” and allows “the secretary to come here and lie.”

“I’m not a liar,” Nielsen replied, saying those were “fighting words.”

“We never had a policy for family separation. A policy of family separation would mean that any family that I encountered in the interior, I would separate. It would mean that any family I found at port of entry, I would separate,” Nielsen explained. “It would mean every single family that I found illegally crossing, we would separate. We did none of those. What we did do is uphold the laws that congress has passed and we prosecuted those who choose to come here illegally.”

Gutierrez them promptly walked out the hearing.

“He couldn’t be bothered to stay,” Nielsen said as Gutierrez was storming out. “So I’m happy to tell the rest of the committee [about combating human trafficking].”

Addressing charges that she has not been “compassionate,” Nielsen said: What we have done is we’ve worked extensively with the northern triangle countries to find ways to help vulnerable populations as soon in their journey as possible.”

“The current system puts them at the hands of those who prey on them and abuse them. So we’ve worked extensively to increase asylum capacity to help them as soon as possible,” she said.

Nielsen added that the administration has “worked on child exploitation, live abuse, where somebody goes online and directs an abuser how to as they watch. That is a crime that DHS investigates and prosecutes.” She said her administration has also worked against traffickers, enacted anti-smuggling and anti-trafficking strategies, and helped survivors.

“I take personal offense on behalf of the 240,000 men and women of the Department of Homeland Security,” she concluded in response to Gutierrez’s accusations.