The progressive messaging operation Media Matters for America re-tweeted and criticized a Bill O’Reilly parody account during coverage of Wednesday’s shooting in San Bernardino, unaware that the O’Reilly account was fake.

“This Bill O’Reilly tweet on San Bernardino is promoting a hoax,” Media Matters tweeted Wednesday night, referring to a tweet sent by the account @oreillyfactor identifying white supremacist “Sam Hyde” as one of the shooters in San Bernardino.

Media Matters, led by pro-Hillary Clinton operative David Brock, then linked to a 4chan post to prove that O’Reilly’s claim was “Debunked.”

But the hoax was on Media Matters.

@oreillyfactor, which purports to be Bill O’Reilly, is a fake account with only 89 followers that intentionally tweets out false information, presumably to try to trick unsuspecting news organizations into reporting things that O’Reilly never said.