Emmett Till
Emmett Till is seen lying on a bed in this undated photo. Getty Images

Relatives of civil rights icon Emmett Till, the black teenager who was lynched in Mississippi in 1955, have called for a new investigation after a key witness admitted she lied during the ensuing trial. Wheeler Parker and Deborah Watts, cousins of Till, have said that authorities should reopen the investigation into the lynching that galvanized the modern civil rights movement, the Associated Press reported Wednesday.

The call for a new look into Till's case come after Carolyn Bryant Donham admitted to a Duke University professor that she lied when she told a jury 14-year-old Till made sexual comments to her and grabbed her before he was murdered. Donham admitted her fabrication in 2007, at 72 years old, to Timothy B. Tyson, whose book "The Blood of Emmett Till," was released last week. Vanity Fair first reported on Donham's admission in late January.

Till was visiting relatives in Money, Mississippi, from his home in Chicago in 1955 when he had an interaction with 21-year-old Donham, then named Carolyn Bryant, at a local store. Some witnesses claimed Till whistled at Bryant, although others said the boy simply had a lisp. A few days later he was kidnapped, beaten, tortured and shot in the head before his body was thrown in the Tallahatchie River. Donham's husband at the time, Roy Bryant, and his half brother, J.W. Milam, were charged with murder.

During the trial, Donham took the stand and said Till grabbed her and threatened her. An all-white, all-male jury acquitted the two men, who later confessed to the murder in Look Magazine

But Donham, who broke decades of silence to speak with Tyson, admitted her description of her interaction with Till wasn't true. She also said she was physically abused by Bryant.

“The circumstances under which she told the story were coercive,” Tyson told the New York Times. “She’s horrified by it. There’s clearly a great burden of guilt and sorrow."

In 2004, the Justice Department and FBI decided to conduct a new investigation to see if any surviving perpetrators could still be prosecuted. Donham repeated her original story to investigators, and, in 2007, the investigation was closed after a grand jury declined to hand down any indictments in connection with the case.

But it seems Donham has escaped the possibility of prosecution. There is a five-year statute of limitations on giving false testimony.

“It appears that time has once again robbed us of justice in the Emmett Till case,” former U.S. Attorney Doug Jones told USA Today Tuesday.

Till's mother, Mamie Mobley, insisted on an open casket at the boy's funeral to show America what had been done to her son. Pictures of the funeral in Jet Magazine helped launch the modern civil rights movement. Till's casket was eventually displayed at the Smithsonian.