Where a prosecutor corroborates a witness’ testimony and vouches for its credibility, the prosecutor had acted improperly, and if the evidence is closely balanced, the decision must be reversed and remanded for a new trial.The Illinois Appellate Court, 1st District reversed and remanded a decision by Cook County Circuit Judge Vincent M. Gaughan.On April 20, 2009, police pulled over a vehicle identified as one used in a drive-by shooting.Inside the vehicle were Kerry Williams, the defendant, as well as Michael …