Some residents, politicians question credibility of investigation in Missouri teen's shooting

FILE - In this Feb. 10, 2011, file photo, St. Louis County Prosecuting Attorney Bob McCulloch speaks in St. Louis. The coming days and weeks will be crucial as grand jurors began hearing evidence that will help determine whether Ferguson police officer Darren Wilson is charged with a state crime for the Aug. 9 shooting of 18-year-old Michael Brown. The state’s case is being overseen by McCulloch, who is white, and remains in charge despite mounting pressure to step aside from some local residents and black St. Louis area officials who believe he cannot be impartial. (AP Photo/Tom Gannam, File) (The Associated Press)

The Missouri authorities leading the investigation into the shooting of an unarmed black teenager by a white police officer are increasingly facing questions about whether they can be impartial.

Grand jurors will be hearing evidence over the coming weeks that will help determine whether state charges will be brought against Ferguson officer Darren Wilson for the Aug. 9 shooting of 18-year-old Michael Brown.

The case is being overseen by St. Louis County Prosecutor Bob McCulloch.

But some local residents and prominent black politicians have been calling on McCulloch to step aside and allow a special prosecutor to take over. They believe McCulloch, who is white, will favor the officer.

Special prosecutors have been used in some high-profile cases elsewhere.

McCulloch is pressing forward and defending his ability to be fair.