– Tens of thousands of people wanted by law enforcement officials have been removed this year from the FBI criminal background check database that prohibits fugitives from justice from buying guns.

The names were taken out after the FBI in February changed its legal interpretation of “fugitive from justice” to say it pertains only to wanted people who have crossed state lines.

What that means is that those fugitives who were previously prohibited under federal law from purchasing firearms can now buy them, unless barred for other reasons.

Since the National Instant Criminal Background Check System (NICS) was created in 1998, it has prevented 1.5 million people from buying guns, including 180,000 denials to people who were fugitives from justice, according to government statistics.

It is unclear how many people may have bought guns since February who previously would have been prohibited from doing so.

Attorney General Jeff Sessions sent a memo Wednesday to the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives instructing them to take several steps to improve NICS.

The system, he said, is “critical for us to be able to keep guns out of the hands of those … prohibited from owning them.”

The criminal background check system has come under scrutiny in recent weeks after the Air Force said it failed to follow policies for alerting the FBI about the domestic violence conviction of Devin Kelley, who killed more than two dozen churchgoers in Sutherland Springs, Texas, this month. Because his conviction was not entered into NICS, Kelley was allowed to buy firearms.

The interpretation of who is a “fugitive from justice ” has long been a matter of debate in law enforcement circles — a dispute that ultimately led to the February purging of the database.

For more than 15 years, the FBI and ATF disagreed about who exactly was a fugitive from justice.

The FBI, which runs the criminal background check database, had a broad definition and said that anyone with an outstanding arrest warrant was prohibited from buying a gun. But ATF argued that, under the law, people are considered fugitives from justice only if they have a warrant and have also traveled to another state.

In a 2016 report, Inspector General Michael Horowitz urged the Justice Department to address the disagreement “as soon as possible.” Late last year, before President Donald Trump took office, the Justice Department Office of Legal Counsel sided with ATF and narrowed the definition of fugitives, according to law enforcement officials. The office said that gun purchases could be denied only to fugitives who cross state lines.

After Trump was inaugurated, the Justice Department further narrowed the definition to those who have fled across state lines to avoid prosecution for a crime or to avoid giving testimony in a criminal proceeding.

On Feb. 15, the FBI directed its employees in the Criminal Justice Information Services Division to remove all entries of fugitives from justice from the background check database and said that “entries will not be permitted” under that category until further notice. Before the FBI memo, there were about 500,000 people identified as fugitives from justice in the database — and all of those names were removed.