By Jonathan Allen ST. PAUL, Minn. (Reuters) -A federal prosecutor told a jury in closing arguments on Tuesday that three former Minneapolis police officers ignored their training and basic human decency by failing to intervene when their colleague knelt on George Floyd’s neck leading to his death. Tou Thao, 36; J. Alexander Kueng, 28; and Thomas Lane, 38, have all pleaded not guilty to charges they willfully denied Floyd’s right to receive medical aid in police custody during the May 2020 arrest even as they had what a prosecutor called “front-row seats” to Floyd’s murder beside a police car p…