article_snippet: The mother of an unarmed teenager shot dead by police in Madison, Wisconsin, says that similar killings throughout the country have become 'an epidemic'.
article_snippet: A string of unarmed black men killed by police last summer set off a series of protests after the deaths.
article_snippet: Subsequent decisions by grand juries in St Louis and New York not indict the officers involved intensified demonstrations that coalesced under the slogan 'black lives matter'.
article_snippet: Police killings of unarmed black civilians have led to waves of protests against perceived brutality and bias.