Jeopardy! contestant Kelly Donohue condemned white supremacy and said there was a “terrible misunderstanding” after hundreds of former players put their names on a furious open letter demanding an apology after he appeared to flash a hand gesture used by white supremacists on the air. On Tuesday’s episode, Donohue arranged his hand in a way that looked similar to the upside-down “OK” sign adopted by some racists.

In an updated Facebook post Thursday morning, Donohue said he was “truly horrified” and that “people who know me personally know that I am not a racist, but for the public at large it bears repeating: I am not a racist and I reject and condemn white supremacy and all forms of bigotry for the evil they are. It’s shameful to me to think anyone would try to use the stage of Jeopardy! to advance or promote such a disgusting agenda. During the taping of my fourth episode, I was simply raising three fingers to mark my 3rd win. There was nothing more I was trying to indicate. I deeply regret this terrible misunderstanding. I never meant to hurt a soul and I assure you I am no friend of racists or white supremacists.”

The open letter, signed by more than 500 former contestants, said that, whether Donohue made the sign with bad intentions or not, it shouldn’t have made it to air, and they are now asking for “a statement and a disavowal” from the show’s production team. Representatives for Jeopardy! haven’t officially commented on the controversy.