Donald Trump isn't buying the claims by senior staffers on Hillary Clinton's campaign that they were "unaware" the father of Orlando shooter Omar Mateen was in attendance at her campaign rally on Monday.

"Wasn't it terrible when the father of the animal that killed the wonderful people in Orlando was sitting with a big smile on his face right behind Hillary Clinton?" Trump asked the crowd at his own rally in South Florida on Wednesday.

"How many of you people know me?" the Republican presidential nominee turned and asked those sitting behind him. "When you get those seats, you sort of know the campaign. So when she said, 'well, we didn't know' — he knew, they knew."

"How did you like that picture? Him sitting, 49 people killed, other people will never ever be the same, and that guy is sitting back there," Trump said, referring to photographs of Siddique Mateen seated closely behind Clinton.

Trump continued. "Of course he likes Hillary because Hillary won't even say the words radical Islamic terrorism. Of course he likes her."

Nearly 48 hours after Clinton's rally had concluded, her campaign issued a statement claiming Mateen "wasn't invited as a guest and the campaign was unaware of his attendance until after the event."

"The rally was a 3,000-person, open-door event for the public," noted a campaign spokesman.

Mateen later endorsed Clinton, telling a local reporter that she "is good for the United States versus Donald Trump, who has no solutions."