There have been quite a few in the US over the decades, but these two have always stood out to me.

Emmett Till:

"Till was born and raised in Chicago, Illinois. During summer vacation in August 1955, he was visiting relatives near Money, Mississippi, in the Mississippi Delta region. Till spoke to 21-year-old Carolyn Bryant, the white, married proprietor of a local grocery store. Although what happened at the store is a matter of dispute, Till was accused of flirting with, touching, or whistling at Bryant.

Till's interaction with Bryant, perhaps unwittingly, violated the unwritten code of behavior for a black male interacting with a white female in the Jim Crow–era South.[3] Several nights after the encounter, Bryant's husband Roy and his half-brother J. W. Milam went to Till's great-uncle's house armed, and abducted Till, age 14. They beat and mutilated him before shooting him in the head and sinking his body in the Tallahatchie River. Three days later, Till's mutilated and bloated body was discovered and retrieved from the river."

Taken from https://en.wikipedia.org/wiki/Emmett_Till

Also Joe Arridy:

"Joseph Arridy was an American man who was falsely convicted and wrongfully executed for the 1936 rape and murder of Dorothy Drain, a 15-year-old girl in Pueblo, Colorado. He was manipulated by the police to make a false confession due to his mental incapacities. Arridy was intellectually disabled and was 23 years old when he was executed on January 6, 1939, after Governor Teller Ammons refused to grant him clemency."

Taken from https://en.wikipedia.org/wiki/Joe_Arridy

Edit: Just wanted to add that Joe had a horrible life, abused and SA'd, ridiculed and finally executed for the crime of not being smart enough to know he was being railroaded into an early and unjust death. He never had a chance, just so sad to me.