Only two people knew exactly what happened during the minute they were alone together in the general store in Money, Miss., on Aug. 24, 1955. One, Emmett Till, a Black teenager visiting from Chicago, died four days later, at 14, in a brutal murder that stands out even in America’s long history of racial injustice.

The other was Carolyn Bryant. She was the 21-year-old white proprietress of the store where, according to her testimony in the September 1955 trial of her husband and his half brother for the murder, Emmett made a sexually suggestive remark to her, grabbed her roughly by the waist and let loose a wolf whistle.

Now Mrs. Bryant, more recently known as Carolyn Bryant Donham, has died at 88. On Thursday, Megan LeBoeuf, the chief investigator for the Calcasieu Parish coroner’s office in Louisiana, sent a statement confirming the death, on Tuesday, in Westlake, a small city in southern Louisiana. Ms. LeBoeuf did not provide further information.

With Mrs. Bryant’s death, the truth of what happened that August day may now never be clear. More than half a century after the murder, Timothy B. Tyson, a Duke University historian who interviewed her, wrote that she had admitted to him that she had perjured herself on the witness stand to make Emmett’s conduct sound more threatening than it actually was — serving, in Dr. Tyson’s words, as “the mouthpiece of a monstrous lie.”

“She said with respect to the physical assault on her, or anything menacing or sexual, that that part isn’t true,” Dr. Tyson told “CBS This Morning” in 2017.

The publication of his book on the case, “The Blood of Emmett Till” (2017), prompted the Justice Department to reopen an investigation, in which it subpoenaed Dr. Tyson’s research materials. The federal authorities said Mrs. Bryant denied ever having changed her story, and they questioned Dr. Tyson’s claims, saying a tape recording of an interview that he had conducted with her, which he had provided to investigators, did not contain any sort of recantation. They closed the case in 2021 without bringing charges.