CHICAGO (CBS) — The jury has been chosen, and the trial of one of two two men charged with murdering an off-duty Chicago police officer in March is set to begin Tuesday.

Jovan Battle was standing next to his friend Menelik Jackson when Jackson fired more than 20 shots into a car full of people in March.

Officer John Rivera and three others were in the car.

Rivera was fatally shot in the back while trying to shield his girlfriend from bullets.

Police say Jackson shot “the first Hispanic man that he came in contact with” after he and Battle got into a fight wither another group outside of the River North McDonald’s.