CHICAGO (AP) — Jurors are now deliberating in the case of a white Chicago police officer charged with murder in the 2014 shooting of black teenager Laquan McDonald.

Officer Jason Van Dyke is charged with first-degree murder, aggravated battery and official misconduct in the 2014 shooting of McDonald. But the judge told jurors on Thursday that they can consider the lesser charge of second-degree murder during their deliberations.

Jurors can find him guilty of second-degree murder if they find that Van Dyke believed that he was justified in using deadly force but that that belief was unreasonable.

Prosecutors contend the shooting was not justified. Van Dyke’s attorneys argue that Van Dyke was in fear for his life and acted properly in shooting the 17-year-old, who was armed with a knife.

Key in the trial is video that shows Van Dyke opening fire as McDonald walks at an angle away from him. Attorneys sparred during closing arguments over what the video actually proves.