Bobby Ray Bordeaux had obtained a concealed carry permit in 2004 and used to take a handgun everywhere. He was also an alcoholic and heavy user of marijuana with a long history of depression, according to court records. He had been hospitalized repeatedly for episodes related to his drinking, including about a year before, when he shot himself in the chest with a pistol while drunk in an apparent suicide attempt. Mr. Bordeaux, then 48, started drinking heavily at age 13. He had been taking medication for depression but had not taken it the day of the shooting, he later told the police. He also said he had 15 beers and smoked marijuana that night and claimed to have no memory of what occurred. He was eventually convicted of first-degree murder and assault with a deadly weapon inflicting serious injury.

John K. Gallaher III, a permit holder since 2006, was also an alcoholic with serious mental health issues, said David Hall, the assistant district attorney who prosecuted him for murder. In May 2008, Mr. Gallaher, then 24, shot and killed a friend, Sean Gallagher, and a woman, Lori Fioravanti, with a .25-caliber Beretta after an argument at his grandfather’s home. The police found 22 guns, including an assault rifle, at his home. Mr. Gallaher pleaded guilty to two counts of first-degree murder last year.

Among the other killings: three months after receiving his permit in July 2006, Mark Stephen Thomas killed Christopher Brynarsky with a handgun after an argument at Mr. Brynarsky’s custom detail shop. In 2007, Jamez Mellion, a permit holder since 2004, killed Capt. Paul Burton Miner III of the Army by shooting him 10 times with two handguns after finding him with his estranged wife. William Littleton, who obtained a permit in 1998 and was well known to the police because of complaints about him, shot his neighbor to death with a rifle in 2008 over a legal dispute.

More common were less serious gun-related episodes like these: in July 2008, Scotty L. Durham, who got his permit in 2006, confronted his soon-to-be ex-wife and another man in the parking lot of Coffee World in Durham and fired two shots in the air with a .45-caliber Glock. Antoine Cornelius Whitted, a permit holder since 2009, discharged his semiautomatic handgun during a street fight in Durham last year. Jerry Maurice Thomas, a permit holder since 2009 whose drinking problems were well known to the authorities, held a gun to his girlfriend’s head at his house in Asheville last year, prompting a standoff with the police.

Falling Through the Cracks

Gun rights advocates in North Carolina, as well as elsewhere, often point to the low numbers of permit revocations as evidence of how few permit holders break the law. Yet permits were often not suspended or revoked in North Carolina when they should have been.

Charles Dowdle of Franklin was convicted of multiple felonies in 2006 for threatening to kill his girlfriend and chasing her to her sister’s house, where he fired a shotgun round through a closed door. He then pointed the gun at the sister, who knocked it away, causing it to fire again. Mr. Dowdle was sentenced to probation, but his concealed handgun permit remained active until it expired in 2009.

Mr. Dowdle, 63, said in a telephone interview that although he gave away his guns after his conviction, no one had ever done anything about his permit. He said he “could probably have purchased” a gun with it but had not done so because federal law forbade it.