Writer E. Jean Carroll is requesting a sample of President Donald Trump‘s DNA to corroborate her accusation that the president sexually assaulted her in a Bergdorf Goodman dressing room in the 1990s.

“After Trump sexually assaulted me, I took the black dress I had been wearing and hung it in my closet,” Carroll said in a statement Thursday.

“I only wore it once since then and that was at the photoshoot for the New York Magazine article about my book,” Carroll continued. “Unidentified male DNA on the dress could prove that Donald Trump not only knows who I am, but also that he violently assaulted me in a dressing room at Bergdorf Goodman, and then defamed me by lying about it and impugning my character.”

Trump wrote off her allegations last year as an attempt to sell her new book, prompting Carroll to bring a defamation suit against him.

“She is trying to sell a new book — that should indicate her motivation,” Trump said in a statement. It should be sold in the fiction section. Shame on those who make up false stories of assault to try to get publicity for themselves, or sell a book, or carry out a political agenda.”

The lawsuit claims Trump “knew who she was when he raped her, and he knew who she was in 2019.”

“Trump knew that these statements were false; at a bare minimum, he acted with reckless disregard for their truth or falsity,” the lawsuit reads. “Trump had recognized Carroll on sight at Bergdorf Goodman. He knew who she was when he raped her, and he knew who she was in 2019. He certainly knew that she was telling the truth.”

One of Carroll’s lawyers, Roberta Kaplan, said the DNA request is relevant to the suit and “has become standard operating procedure in these circumstances.”

“This case turns on whether Donald Trump lied when he said that he had not sexually assaulted E Jean Carroll and, in fact, had never even met her,” Kaplan said in a statement. “Testing unidentified male DNA on the dress she wore during that assault has become standard operating procedure in these circumstances given the remarkable advances in DNA technology, particularly where, as is the case here, other potential contributors have been excluded.”

She added, “As a result, we’ve requested a simple saliva sample from Mr. Trump to test his DNA, and there really is no valid basis for him to object.”