A white gunman shot dead nine people in an African-American church in the city of Charleston on 17 June, police say, two months after an unarmed black man was killed by a white police officer in North Charleston.
The killings have reignited the debate about race relations in the US. Here are six surprising statistics that help tell the story.
There are only two black billionaires in the US - chat show host Oprah Winfrey and former basketball star Michael Jordan. This compared with about 500 white billionaires.
Black students appear to do well in high school - just over 30% of over-25s have a diploma, compared with 27% of white over-25s. But fewer than 10% of black over-25s completed a bachelor's degree, compared with 14.4% of whites.
A survey conducted by the Public Religion Research Institute in 2013 asked a range of questions to assess how diverse people's friendship groups were. It found that while 65% of black Americans reported only having black friends, 75% of white Americans said they had only whites in their social circle.
Unemployment remains far higher among the black population, than the white. Currently 4.8% of white Americans are out of work, compared with an overall average of 5.8%
Figures based on the prison population at the end of December 2013 show black Americans made up a disproportionate number of inmates. Some 32% were white and 22% Hispanic.
Data sources: US Census, Public Religion Research Institute, Forbes, US Dept of Labor, US Dept of Justice
Correction: An earlier version of this story did not make clear that the figures for people with high school diplomas or bachelor's degrees were for those aged over 25.