A South Side man seeking to avenge an earlier shooting killed Chicago Police Officer Alejandro "Alex" Valadez in a volley of bullets, then drove to a friend's house where he partied with his buddies, prosecutors told jurors today as his trial opened.

Shawn Gaston, 22, is the first of three alleged gang members to go to trial in the fatal shooting of Valadez in June 2009 as he investigated a call of shots fired in the Englewood neighborhood. Eric Walker and Christopher Harris will go to triel next.

Valadez, 27, was questioning a man on the street when Walker slowed the car and Gaston leaned out of the front passenger window and opened fire. The officer, who was in plainclothes and wearing a ballistic vest, duty belt and his police star, was struck in the head and leg.

Source: Chicago Tribune.