But sitting behind Trump was ex-congressman Mark Foley, who resigned in disgrace in 2006 after sending sexually explicit messages to underage teenage boys.
"When you get those seats, you sort of know the campaign. You sort of know the campaign," Trump said at the rally in Sunrise, Florida. As Trump upbraided Clinton for having Mateen in the stands behind her, Foley smiled, applauded and even waved at Trump.
"How many of you people know me?" Trump asked those seated behind him.
Foley, visible just to Trump's left, quickly raised his hand in response.
The Trump campaign decided on Thursday not to release a statement disavowing Foley, despite the pressure it placed on Clinton to disavow Mateen's father.
The rows of seats directly behind Trump, where Foley was seated, had signs that marked the seats as "RESERVED."
Trump continued to slam Clinton for having Mateen's father seated behind her:
"Of course he likes Hillary because Hillary won't say the words radical Islamic terrorism," Trump said of Mateen's father, who had no knowledge of his son's plot to kill people at an Orlando night club in June.
Clinton's campaign released a statement Tuesday disavowing Mateen's support.
Foley confirmed his attendance to the Sun Sentinel
, telling the newspaper that he arrived early to get his prime seating, visible behind Trump in TV shots -- just like he used to do during the State of the Union addresses when he was in Congress.
Foley has previously publicly expressed his support for Trump, appearing in the audience as Trump delivered remarks to a relatively small group of supporters at his Mar-a-Lago estate in March the night of the Florida Republican primary.
"I've been a friend of Mr. Trump's since 1987. I've admired so much of what he's done. He's a different breed of leader and a different breed of candidate," Foley told the Sun Sentinel.
Foley resigned from Congress in 2006 after a 12-year tenure amid reports that he exchanged sexually explicit instant messages with a 16-year-old former congressional page, and sent suggestive messages to other underage teenagers.
The Florida Department of Law Enforcement investigated Foley
, but did not pursue charges, citing "insufficient evidence."