But in the wake of the killing, Mr. Hill’s family members focused on what they described as the failure of Officer Olsen and the Police Department to respond appropriately to a man who suffered from post-traumatic stress disorder. According to court filings and witnesses, Officer Olsen was sent to Mr. Hill’s apartment complex in Chamblee, northeast of Atlanta, while the man was in the midst of what his family described in a lawsuit as “a nonviolent mental episode.” He had, for instance, repeatedly jumped from the balcony of his second-floor apartment, and his speech was unintelligible.

After the arrival of Officer Olsen, who had a Taser device and had received training about how to deal with people suffering from mental illness, witnesses said that Mr. Hill did not comply with the officer’s directions to stop his advance. Mr. Hill’s hands, they said, were raised or at his sides before Officer Olsen opened fire. Mr. Hill, his family said in a court document last year, “was unarmed, unclothed and displaying no signs of aggression at the time of the shooting, and he presented no threat to Officer Olsen or anyone else.”

Image Anthony Hill, a 27-year-old Air Force veteran, was in the midst of what his family described in a lawsuit as “a nonviolent mental episode.”

Mr. Hill’s family has filed a wrongful-death lawsuit, in Federal District Court in Atlanta, against Officer Olsen and the county.

In the lawsuit, which is pending, Mr. Hill’s family said Officer Olsen had “a long and extensive history of aggressive conduct” and “propensity toward anger when dealing with members of the public.” On Thursday, Mr. Samuel described Officer Olsen as “a distinguished member of the Police Department who had never been accused of using excessive force and had never previously discharged his firearm in the line of duty.”

But the official investigation into Officer Olsen’s conduct, not the federal lawsuit, has consumed much of the attention here. That inquiry included the closed-door reviews by civil and criminal grand juries. In October, the civil panel, an advisory group, recommended that officials continue their investigation into Mr. Hill’s death.

During an appearance before the civil grand jury, Mr. Hill’s family has said, Officer Olsen said he had believed that Mr. Hill was under the influence of a substance like PCP, and that he had “cast the blame for the shooting” on the Police Department.