evidence: A year has passed since George Floyd - an unarmed African American man - was murdered during an arrest by white officer Derek Chauvin. Videos of the incident - which showed Chauvin kneeling on Mr Floyd's neck for several minutes - triggered protests across the US and around the world over police brutality and racism in law enforcement. [...] Chauvin, 44, placed his left knee on Mr Floyd's neck and shoulder, and kept it there for more than nine minutes, according to prosecutors. Two other officers helped pin him down, while another prevented witnesses from intervening.