Seddique Mateen, the father of the gunman who killed 49 people in Orlando in June, could be seen behind Clinton during a rally she held in Florida Monday. Alan Diaz AP

The father of the Orlando gunman who killed 49 people at a gay nightclub in June attended a Hillary Clinton rally in Florida Monday, appearing behind the candidate as she talked about the economy and acknowledged the shooting his son committed.

Seddique Mateen could be seen standing in the crowd behind Clinton, in a blue shirt and mustache, for nearly half an hour, WPTV first reported. He remained in the audience as Clinton noted the shooting at Pulse nightclub during her speech in Kissimmee, acknowledging “how many people, families, loved ones, and friends are still grieving.”

Mateen, when asked by WPTV about her reference to the shooting, would only say he had “been cooperating with the federal government.” But in another interview a few hours later, he added that he had already spoken “a lot about that.”

He told WPTV he wished his son had “joined the Army and fought ISIS — that would be much better,” he said.

The Clinton campaign told CNN after the event that it had not known about Mateen’s appearance, and it was unclear who had seated Mateen visibly behind the candidate. “The rally was a 3,000-person, open-door event for the public,” an aide told CNN. “This individual wasn’t invited as a guest and the campaign was unaware of his attendance until after the event.”

The rally is not Mateen’s first brush with politics: He ran as a fringe candidate for president of Afghanistan, spent money airing his own news show and pledged support for the Taliban, according to the Washington Post.

Mateen described himself as a Democrat to WPTV and praised Clinton as “good for the United States versus Donald Trump, who has no solutions.”

He defended his right to attend the rally when WPTV asked if he thought some might be surprised at his appearance. “Why should they be surprised? I love the United States and I’ve been living here a long time,” Mateen said.

This story includes information from the Washington Post.