The US Justice Department will not prosecute a former Ferguson, Missouri, police officer in the shooting death of an unarmed black 18-year-old, but in a scathing report released on Wednesday faulted the city and its law enforcement for racial bias. Federal officials concluded there was no evidence to disprove testimony by former officer Darren Wilson’s, who is white, that he feared for his safety, nor was there reliable evidence that Michael Brown had his hands up in surrender when he was shot.