Years of dialogue about police and criminal justice reforms in Minneapolis had improved the relationship between the African American community and law enforcement, activists say — before the police killing this week of George Floyd, a handcuffed black man who died after a white officer pressed his knee into Floyd’s neck for several minutes as he pleaded for air. Floyd’s death and footage of the officer pressing a knee into his neck for several minutes have unleashed protests and violent clashes with law enforcement — exposing simmering frustration and the fact that there’s much work still ahead, several advocates and leaders told The Associated Press.