Sen. Elizabeth Warren (D-Mass.) is asking Donald Trump to make good on a $1 million bet, but Trump’s memory of the bet is fuzzy.

Trump promised to donate $1 million to the charity of Warren’s choice if she released the results of a genetic test that proved Native American heritage. Trump has claimed Warren used a false story of Native American heritage to further her career as a professor at Harvard Law. On Monday Warren released the results of a test administered by an genetics expert showing a Native American ancestor within six to ten generations of the senator.

Warren has since asked Trump to donate to the National Indigenous Women’s Resource Center, whose mission is to “enhance the safety of Native women and their children.” 

Trump, who often refers to Warren as “Pocahontas,” denied he made the bet in a gaggle with reporters Monday. 

But Trump made headlines at a rally in July for this taunt: “I’m going to get one of those little kits and in the middle of the debate when she proclaims she’s of Indian heritage because her mother said she has high cheekbones.”

“We will take that little kit and say — and we have to do it gently because we’re in the Me Too generation, so we have to be very gentle — and we will very gently take that kit and we will slowly toss it, hoping it doesn’t hit her and injure her arm even though it probably only weighs two ounces,” Trump continued. “And we will say, ‘I will give you a million dollars to your favorite charity paid for by Trump if you take the test, and it shows you’re an Indian.”

Republicans’ allegation about Warren originated with GOP opposition research released during her 2012 Senate race. A spokesman for Harvard Law School cited Warren’s ancestry in order to tout the faculty’s diversity in an interview with the university newspaper, the Boston Globe reported at the time.

Some Native American leaders are troubled by Warren’s use of a DNA test to claim Native heritage.

The Cherokee Nation said the test hurts the tribe’s interests in a statement Monday night.

“Using a DNA test to lay claim to any connection to the Cherokee Nation or any tribal nation, even vaguely, is inappropriate and wrong,” Cherokee Nation Secretary of State Chuck Hoskin Jr. said.

A DNA test “really doesn’t drill down to the question of whether somebody has Cherokee ancestry, for example, or ancestry of any particular tribe,” Hoskin said in an interview with CNN. “We need to be clear about what it means to be Native American, an Indian in this country. And it frankly comes down to a legal status that we have fought long and hard for and are very proud of.”

Warren’s thorough counter-messaging signals a likely 2020 presidential run.

Warren faces re-election next month against Republican Geoff Diehl in a race rated Solid Democratic by Inside Elections with Nathan L. Gonzales.

Watch: Elizabeth Warren Reveals DNA Results and Talks Heritage With Family