Trial begins for suspect in officer's murder

September 19, 2011 9:18:48 AM PDT
Jury selection begins Monday in the trial of one of three men charged with the murder of a Chicago police officer.

Shawn Gaston is accused of fatally shooting Alejandro Valadez in June of 2009.

Officer Valadez was responding reports of gunfire on Chicago's South Side when he was killed.

Cook County State's Attorney Anita Alverez plans to serve as lead prosecutor in this trial.