A deadly traffic stop where plainclothes Chicago police officers fired nearly 100 shots in under a minute has raised serious questions about the use of force and role of tactical officers in departments.As family and community members mourn 26-year-old Dexter Reed, a police oversight agency and Cook County prosecutors are investigating.Videos and documents released this week by the Chicago Office of Police Accountability paint a harrowing picture of what happened during the March 21 traffic stop. But about a week ago, the …