(CBS) – An explosive admission in the 1955 murder of a black Chicago teen whose death sparked the civil rights movement.

Carolyn Bryant Donham, the white woman who claimed Emmett Till whistled at her, now says she did not tell the truth in court, according to a new book.

The body of the 14-year-old was found a few days after the incident in Mississippi. His mother wanted the world to see his mutilated body, so she insisted on an open casket.

Donham testified at her husband’s trial that Till had grabbed her and threatened her. Her spouse and a co-defendant were acquitted by an all-white jury.

In an interview conducted for a book due out next week, Donham is quoted as saying she exaggerated. She also reportedly says she felt sorry for Till’s mother.

Chris Benson, an associate professor of journalism at the University of Illinois at Chicago, says people have doubted Donham’s claims and her recent acknowledgement will be a relief to them.

He says this should prompt us to be more open-minded when looking at current conflicts between minorities and law enforcement.

Benson wrote a book with Emmett Till’s mother, Mamie Till-Mobley, before she died in 2003.