Updated

A Missouri grand jury could begin hearing evidence Wednesday in the shooting death of a black teenager by a white police officer in suburban St. Louis.

St. Louis County Prosecuting Attorney Bob McCulloch is overseeing the case that will determine whether Ferguson police officer Darren Wilson faces criminal charges for the Aug. 9 shooting death of 18-year-old Michael Brown.

McCulloch spokesman Ed Magee said Monday that prosecutors would try to start presenting evidence Wednesday, the regular once-a-week meeting date for the grand jury.

Cases often are presented to grand jurors in a single day. But Magee says Brown's case is complicated and will take longer, though he gave no specific timeline.

Brown's death has sparked violent clashes between police and protesters who want the officer to be charged.