Attacking Hillary Clinton in the second presidential debate, Donald Trump on Sunday said if he won the White House, he would put her in jail for operating a private email server while she served as the US secretary of state.

During the contentious debate, Trump said he would appoint a special prosecutor to look into his Democratic rival’s email use because she had endangered national security during her tenure as President Barack Obama’s chief diplomat from 2009-2013.

The 90-minute debate got off to a chilly start when the two candidates for the November 8 election greeted each other without the traditional handshake.

Trump attacked Clinton over the emails, saying: “You ought to be ashamed of yourself.”

Clinton said, “You know it’s just awfully good that someone with the temperament of Donald Trump is not in charge of the law in this country.” Trump shot back: “Because you’d be in jail.”

A nearly year-long FBI investigation into the emails concluded earlier this year without charges being filed, although FBI Director James Comey said she had been careless in her handling of sensitive material.

Clinton insisted there was “no evidence” that her server had been hacked and that any classified information had ended up in the wrong hands. “I take classified material very seriously,” she said.

Trump said: “You said it was fine to delete 33,000 emails. I don’t think so.”

Clinton shook her head. “Look it’s just not true.”

She accused Trump of dodging a discussion of policy issues to avoid talking about his campaign because of “the way yours is exploding and Republicans are leaving you.”

The debate’s town hall-style format, with undecided voters posing half the questions and the debate’s two moderators posing the others, allowed the candidates to move freely around the stage and address the questioners directly.

Clinton, 68, and Trump, 70, both stood up to answer questions, and Clinton frequently stood directly in front of the questioners in an effort to make a connection with voters. At times Trump stood almost over her shoulder as she addressed the town hall meeting.