Last week, Miller gave a statement to an assistant district attorney.
Officer Reginald Fisher, 40, remains on paid administrative leave, police spokesman Officer James Polite said Tuesday.
Miller's attorney has asked for Fisher to be fired and criminally charged.
Miller said very little as he left Grady on Tuesday with his attorney, reverend and family, for fear he would jeopardize the investigation.
"I thank everyone that supported me and believed in me," he said.
Fisher was working security May 6 at a Richardson Street apartment complex when he saw Miller around 9 p.m., and deemed him "suspicious," police records show.
According to a police report, Fisher told investigators he felt threatened and fired once, hitting Miller in the face.
Police have said that Miller ran to his car and reached under his seat when Fisher approached, service weapon drawn. But witnesses at the scene claim Miller put his hands in the air as Fisher instructed.
Investigators later found no weapons on Miller and have not acknowledged whether a weapon was found in the car.
Fisher's personnel file, obtained by the Atlanta Journal-Constitution using the Georgia Open Records Act, portrayed a rookie officer who'd been on the street for less than a year.
Evaluations in his personnel file — both during his first six months as a police recruit — offered no outstanding marks over his 17-month tenure with the Atlanta Police Department.
According to the evaluations signed in December 2007 and July 2007, Fisher earned "effective" on each of his cricital job element ratings for customer service, procedure and equipment management.
Fisher joined the department after serving with three area fire departments between 2001 and 2007.
He joined the Clayton County Fire Department in May 2001 as a fire fighter and emergency medical technician. Fisher left Clayton after nearly two years, and from 2003 to 2006 was a Forest Park fireman and EMT.
He became an Atlanta firefighter in July 2006, and remained until December 2007 when he joined the Atlanta Police Department.
Tuesday, Davis said Fisher had no probable cause to shoot Miller. Davis said his client was simply dropping off some medication at his aunt's apartment and returning to his car.
"There were no drugs, no gun. This young man was trying to do what he did as a nephew," Davis said.
Miller's supporters questioned why police union president Sgt. Scott Kreher, who threatened to beat Mayor Shirley Franklin with a baseball bat, was punished quicker than Fisher. Kreher was suspended and placed on administrative leave.
"What chance did Tramaine have when a union official would threaten an elected official," Rev. Derrick Rice said. "Clearly there is no concern for life in this particular community."
The bullet shattered Miller's jaw. Several days ago, he began eating soft food. He has trouble sleeping and will be cared for at home by family and a nurse, his attorney said.