WASHINGTON (AP) — President Joe Biden on Tuesday was signing a bill into law to make lynching a federal hate crime, more than 100 years after such legislation was first proposed.

The Emmett Till Anti-Lynching Act is named after the Black teenager whose killing in Mississippi in the summer of 1955 became a galvanizing moment in the civil rights era. His grieving mother insisted on an open casket to show everyone how her son had been brutalized.

The new law, to be signed by Biden in a Rose Garden ceremony, makes it possible to prosecute a crime as a lynching when a conspiracy to commit a hate crime leads to death or serious bodily injury, according to the bill's champion, Rep. Bobby Rush, D-Ill. The law lays out a maximum sentence of 30 years in prison and fines.

The House approved the bill 422-3 on March 7, with eight members not voting, after it cleared the Senate by unanimous consent. Rush also had introduced a bill in January 2019 that the House passed 410-4 before that measure stalled in the Senate.

Congress first considered anti-lynching legislation more than 120 years ago. It had failed to pass such legislation nearly 200 times, beginning with a bill introduced in 1900 by North Carolina Rep. George Henry White, the only Black member of Congress at the time.

The NAACP began lobbying for anti-lynching legislation in the 1920s. A federal hate crime statute eventually was passed and signed into law in the 1990s, decades after the civil rights movement.

Till, 14, had traveled from his Chicago home to visit relatives in Mississippi in 1955 when it was alleged that he whistled at a white woman. Till was kidnapped, beaten and shot in the head. A large metal fan was tied to his neck with barbed wire before his body was thrown into a river. His mother, Mamie Till, insisted on an open casket at the funeral to show the brutality her child had suffered.

Two white men, Roy Bryant and his half-brother J.W. Milam, were accused, but acquitted by an all-white-male jury. Bryant and Milam later told a reporter that they kidnapped and killed Till.