(CNN) Robert "Chip" Olsen was uncomfortable when he saw Anthony Hill running naked outside a Georgia apartment complex, but it didn't give him a reason to shoot and kill him, prosecutors said.

Olsen's attorney countered that his client, who was a Dekalb County police officer at the time of the shooting, was scared and acted in self-defense.

Jurors heard opening statements Thursday in a trial to decide whether Olsen is guilty of murder. The white former officer fatally shot Hill, a black US Air Force veteran who was naked and apparently unarmed.

Hill's killing led to protests in Atlanta that mirrored nationwide demonstrations over race, policing and excessive force in recent police killings.

Defense attorney Don Samuel argued Thursday that his client didn't have a clear picture of Hill's actions or what his background was. He only knew that people had called 911 scared of a man acting up.

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