LEXINGTON, S.C. -- Both the FBI and a county sheriff's department agency promise to review a series of mistakes that allowed South Carolina church shooting suspect Dylann Roof to get a gun he never should have been allowed to buy.
Lexington County Sheriff Jay Koon told The Associated Press on Monday that a clerk at his jail entered in the incorrect location for Roof's drug arrest in February. That meant an FBI examiner using records from a state database couldn't find the details about the arrest when Roof wanted to buy a gun.
The background check found nothing after three days and Roof was eventually allowed to buy the .45-caliber handgun authorities say was used in the June 17 shooting at Emanuel African Methodist Episcopal Church in Charleston that killed nine people.
The jail discovered mistakes two days after Roof's drug arrest, but the change wasn't corrected in the state police database of arrests. So when an FBI examiner pulled Roof's records in April, she called the wrong agency.
FBI Director James Comey on Friday promised a full review when he said Roof should have never been allowed to buy the gun. The sheriff on Monday also promised he was making changes that would flag discrepancies like the one that appeared to let Roof slip through the cracks. He didn't name the employee who made the error or say if the worker faced any discipline.
The FBI allows a gun sale if it can't give a definitive answer about whether someone can buy the gun after three days, which is what happened in Roof's case. The FBI examiner knew Roof had an arrest record, but couldn't find the documents.
CBS News' Paula Reid reported that federal law bans the sale of a firearm to "an unlawful user of or addicted to any controlled substance."
Roof was arrested in March for possession of Suboxone, a Schedule III prescription drug used to treat addiction to opioids. According to the police report, he had admitted using it. Even if he hadn't been convicted of the crime, the FBI says the admission of drug use should have been enough to trip the background check.
In 2014, the FBI reported about 2 percent of background checks end with the FBI not getting enough information and failing to give an answer. Officials said they do about 58,000 checks on a typical day, handled by about 500 people at a call center.
There were a couple of mistakes that ended up in the criminal records database. State police records of Roof's drug arrest pulled by the AP minutes after he was identified as the church shooting suspect had the drug charge listed as a felony with the arresting agency as Lexington County Sheriff's Office. They have since been corrected. The charge is a misdemeanor and the arresting agency was the Columbia police department.
Koon, the sheriff, said that when the FBI examiner called his deputies, they pointed out the arrest was by Columbia Police. But the woman doing the FBI background check checked a spreadsheet of law enforcement agencies in Lexington County and it did not include Columbia because it is mostly in neighboring Richland County. The examiner called the police department in West Columbia - where the gun was bought - and found nothing.
Only a very small part of Columbia is in Lexington County, and the city's jurisdiction includes the entire Columbiana Centre mall where Roof was arrested. The officer searched Roof and found a drug doctors use to treat narcotic addiction without a prescription, according to a police report.
That information should have been enough to prevent Roof from buying a gun based on a federal law banning gun sales to anyone who uses or is addicted to a controlled substance, Comey said.
The FBI examiner also said it sent a fax to prosecutors in Lexington County looking for more information about the arrest and the fax was never answered.
A secretary said chief prosecutor Donnie Myers was in court in Saluda County on Monday. He didn't return a phone message.
Last month, a law enforcement source told CBS News' Pat Milton that a .45 caliber gun was found in the car when Roof was arrested during a traffic stop the day after the shooting. Roof purchased the .45 caliber pistol with $400 his father gave him for his birthday, sources said.