David Nathan Thompson cannot come home to DeKalb County -- at least, not for another 15 years.

Unless the Georgia Supreme Court changes its mind about banishment, Thompson, who is bipolar, is limited to 50 of the state’s less populated counties that form a U as they hug the state lines with South Carolina, Florida and Alabama.

“It’s like banishing a child from their family,” attorney McNeill Stokes said a few days after the state Court of Appeals ruled the practice constitutional. “Georgia has got to stop banishing its citizens -- particularly its mentally-challenged citizens -- to get rid of them.”

Because of Thompson's mental problems, Stokes has asked the state Supreme Court to hear the case even though the court already has ruled twice that it's legal to limit criminals to as few as one of the state’s 159 counties as long as they are not banned from the entire state.

The aim of banishment is to ensure a certain criminal element -- like drug dealers, burglars or prostitutes -- stays away.

“They were problem characters but maybe not problematic enough that [judges] could send them to jail and be rid of them,” said University of Georgia law professor Ron Carlson. “It’s a bit of a Southern tradition.”

Thompson’s crime was aggravated assault. Armed with a 30.06 rifle with a scope, the then 21-year-old fired a bullet into the side of a brick house belonging to a Sandy Springs family related to his stepmother on April 23, 2004. Sheron and Robert Barnaby and their daughter were having dinner at the time.

On that same day, Thompson also shot at a convenience store in North Carolina and a water tower in South Carolina. Then he called his mother and told her what he had done.

Thompson said in Fulton County Superior Court he targeted the Barnabys because he had been denied his inheritance -- specifically, a trash can marked with the University of North Carolina logo. His father had committed suicide in May 1999.

“I was still upset by my father’s death and y’all were keeping me from getting my father’s inheritance," Thompson said in court. "It was never my intention to hurt anyone physically.”

The Barnabys did not respond to requests for comment.

Thompson was sentenced to eight years in prison, later reduced to four years, plus 12 years probation.

He was released in April 2008. He went back to prison in July 2009 for another 18 months after he allegedly threatened a North Carolina woman he met online. He was released again on Dec. 30.

He was allowed to live with his mother in DeKalb County for the first year of probation before his banishment to Ware County in South Georgia (chosen because of its distance from metro Atlanta) took effect. Later he was allowed into 49 other counties so he would have better access to mental health care. He now lives in  Columbus.

The sentence was a "reasonable length" of time in prison while the banishment ensured "the safety of the Barnaby family," Fulton District Attorney Paul Howard said.

The second North Carolina incident, along with angry outbursts, indicated Thompson was dangerous, prosecutors said.

He had admitted he had mental and emotional problems that "created a violent and at times uncontrollable rage," Howard said.

Thompson, 28, insisted in an interview with The Atlanta Journal-Constitution that he has had "no thought of hurting" the Barnabys.

“I’m basically in a prison without walls,” Thompson said.

But his written comments during an online discussion of his case questioned the effectiveness of his banishment.

“How can the banishment be enforced?” Thompson said in a post he confirmed he made on onlineAthens.com. “There's nothing stopping me from coming to Atlanta if I really wanted to. ... There is no border patrol protecting the victim."