Hillary Clinton held a rally in Kissimmee, Florida on Monday night and spoke about the Pulse nightclub massacre as Seddique Mateen, the father of shooter Omar Mateen, looked on. The Clinton campaign had no idea the shooter's father was in attendance.

“I know how many people, families, loved ones, and friends are still grieving, and we will be with you as you rebuild your lives, as you rebuild hope for the future.” said Clinton. “Because we can't ever let that kind of hatred and violence break the spirit, break the soul of any place in America.”

https://www.youtube.com/watch?v=yfdR-hYsXts

Mateen, whose son took the lives of 49 people on June 12 at the deadliest mass shooting in U.S. history, was spotted in the crowd standing behind Clinton wearing a red cap (see screencap above).

RELATED: Orlando Shooter's Father Says Omar Mateen Was Angry Over Two Men Kissing

WPTV spoke to Mateen after the rally:

NewsChannel 5 asked Mateen what he was thinking about when Clinton spoke about the Orlando incident.

“We've been cooperating with the federal government, and that's about it,” he said. “Thank you.” Mateen didn't want to answer any other questions, but just hours later, we ran into him by chance at a rest stop on the way back to West Palm Beach. He wanted to do an interview and show us a sign he made for Clinton.

“Hillary Clinton is good for United States versus Donald Trump, who has no solutions,” he said.

We asked what went into his decision to go to the event right near Orlando, where the Pulse Nightclub shooting happened.

“I spoke a lot about that and wish that my son joined the Army and fought ISIS. That would be much better,” he said.

Watch:

The Clinton campaign said Mateen had not been invited:

Clinton campaign statement part I: "This rally was a 3,000-person, open-door event for the public. This individual wasn't invited as a guest

— Tory Dunnan (@ToryDunnanTV) August 9, 2016