Lawyers for a woman who accuses President Donald Trump of raping her in the 1990s are asking for a DNA sample, seeking to determine whether his genetic material is on a dress she says she wore during the encounter.

Advice columnist E. Jean Carroll’s lawyers served notice to a Trump attorney Thursday for Trump to submit a sample on March 2 in Washington for “analysis and comparison against unidentified male DNA present on the dress.”

Carroll filed a defamation suit against Trump in November after the president denied her allegation. Her lawyer, Roberta Kaplan, then had the black wool coat-style dress tested. A lab report with the legal notice says DNA found on the sleeves was a mix of at least four people, at least one of them male.

Several other people were tested and eliminated as possible contributors to the mix, according to the lab report, which was obtained by The Associated Press. Their names are redacted.