Donald Trump said if he wins the White House he will appoint a special prosecutor to investigate Hillary Clinton’s use of a private email server while she was secretary of state, and threatened to put her in jail over the issue during their bitterly contested second debate on Sunday night.

Trump and Clinton attacked each other for about 90 minutes in St. Louis in the wake of an explosive recording made public on Friday that featured Trump making sexually aggressive comments about women. The tape dominated the early part of the contentious debate, with Trump dismissing his remarks as “locker room talk.”