ORK, Pa. (AP) — A black woman who watched a white mob kill her sister during race riots nearly a half-century ago in Pennsylvania – and had to wait over 30 years for justice – has died.

Hattie Dickson died of natural causes Monday at York Hospital, said Lucy Gladfelter of Gladfelter Funeral Home. She was 70.

Long-simmering racial tensions in York, Pa., erupted in violence in the summer of 1969. On July 18, 1969, white police officer Henry Schaad was shot and killed.

Four days later, Dickson was behind the wheel when a mob of armed white youths confronted her family after their car got stuck at a railroad crossing. Her 27-year-old sister, Lillie Belle Allen, got out of the car to take the wheel from a frightened Dickson, and was gunned down by the mob.

Allen was a mother of two from Aiken, South Carolina, and was in York visiting her sister. Her killing went unpunished until prosecutors reopened the case in 1999.

Eventually, 10 white men were charged, including York’s mayor at the time of prosecution. Two were convicted of second-degree murder; seven others pleaded no contest or guilty to lesser charges, and former York Mayor Charlie Robertson was acquitted.

Dickson, her surviving sister and Allen’s two children were awarded a $2 million settlement from the city in 2005. It settled the lawsuit Allen’s family filed against York and five former police officers.