President Donald Trump on Wednesday lashed out at Rep. Frederica Wilson (D-FL) after she accused him of making insensitive comments to the widow of slain U.S. Army Sgt. David Johnson.

“Democrat Congresswoman totally fabricated what I said to the wife of a soldier who died in action (and I have proof),” Trump wrote. “Sad!”

Trump in the past has bluffed about having “proof” to disprove accusations leveled against him, such as when he warned former FBI Director James Comey that he might have “tapes” of their conversations that would show that Trump didn’t repeatedly ask him for unconditional loyalty.

When pushed to release these tapes, however, Trump eventually acknowledged that no such tapes existed.

Wilson on Tuesday said that Trump told Myeshia Johnson, whose husband was killed in Niger earlier, that Sgt. Johnson “knew what he was signing up for” when he joined the Army, although he did acknowledge that it’s still “sad” when soldiers die.