(CNN) — In a federal lawsuit filed earlier this week, a family member of Emmett Till is demanding that Leflore County Sheriff Ricky Banks serve an arrest warrant from 1955 on Carolyn Bryant Donham for her role in the death of Till.
Last year, a five-member search group, including members of Till's family found an unserved 1955 arrest warrant for Bryant at the Leflore County courthouse.
Till, a 14-year-old boy from Chicago, was visiting family in Mississippi when he had his fateful encounter with then-20-year-old Carolyn Bryant. Accounts from that day differ, but witnesses alleged Emmett whistled at Bryant (now Donham) at the market she owned with her husband in Money, Mississippi.
Later, her husband, Roy Bryant and J.W. Milam, took Till from his bed and ordered him into the back of a pickup truck and beat him before shooting him in the head and tossing his body into the Tallahatchie River. They were both acquitted of murder following a trial in which Carolyn Bryant testified that Emmett grabbed and verbally threatened her.
In 2007, a Mississippi grand jury declined to indict Donham on any charges.
"It was Carolyn Bryant's lie that sent Roy Bryant and J.W. Milam into a rage, which resulted in the mutilation of Emmett Till's body into a [sic] unrecognizable condition," the newly filed lawsuit states.
"The Leflore County Sheriff is complicit in the trio's escape from justice even though both Roy Bryant and J.W. Milam admitted to the crime," it continued.
"To this day, the warrant issued for Carolyn Bryant remains unserved. Carolyn Bryant's whereabouts are known. This action is being brought in order to compel the Lelfore County Sheriff to serve the warrant upon Carolyn Bryant," it added.
CNN has reached out to Banks for comment.