The FBI views the January siege of the U.S. Capitol as “domestic terrorism,” according to Director Christopher Wray, who assured senators on Tuesday that the bureau is working hard to investigate anyone who stormed the halls of Congress.

“I was appalled, like you, at the violence and destruction that we saw that day. I was appalled that you, our country’s elected leaders, were victimized right here in these very halls,” Wray said during his opening statement before the Senate Judiciary Committee on Tuesday. “That attack — that siege — was criminal behavior, plain and simple, and it’s behavior that we — the FBI — view as domestic terrorism. It’s got no place in our democracy, and tolerating it would make a mockery of our nation’s rule of law.”