Why do you think the lynching of emmett till became a catalyst in the national movement for civil rights?

Emmett Till was a teenage boy who was visiting his grandparents in Mississippi when he was killed. Supposedly Emmett whistled at a white female store owner after making a purchase. When the women's husband, Roy Bryant, found out about this situation he recruited JW Milam (his brother in law) to find the boy and punish him.

Ultimately, Bryant and Milam find Emmett Till at his grandparent's house. From there they kidnap him, beat him to death, and then throw him in a river where his body is found a few days later. These two men were accused of homicide but found guilty by an all white jury.

This scenario of brutal violence against a young man who did nothing to hurt anyone is one of the reasons why this was a catalyst for the Civil Rights movement. Millions of Americans all over the country were in shock to hear about the violence and rallied around this scenario as a means to advocate for civil rights.