Story highlights Hillary Clinton was unaware of his presence at the event

Seddique Mateen said he's backing Clinton for president

(CNN) The father of the Orlando gunman attended a Hillary Clinton rally in Florida Monday to show his support for the Democratic candidate.

"Hillary Clinton is good for the United States versus Donald Trump, who has no solutions," Seddique Mateen told WPTV . He could clearly be seen standing behind Clinton as she addressed the audience.

His son, Omar, killed 49 people at the Pulse nightclub, a gay club in Orlando, in June in the worst incident of domestic terrorism since 9/11.

Seddique Mateen, who said he was a Democrat, showed WPTV a sign he had made in support of Clinton, highlighting that he believes she is good for national security and citing gun control laws. Mateen told the reporter that he wants the U.S. to be a safer place.

A Clinton aide said: "The rally was a 3,000-person, open-door event for the public. This individual wasn't invited as a guest and the campaign was unaware of his attendance until after the event."

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