(CNN) Tens of thousands of names were removed from the national criminal background check database this year after the FBI narrowed its interpretation of who is a "fugitive from justice," according to an administration official.

Under the narrowed definition, in place since February, gun purchases can only be denied to fugitives who have crossed state lines to avoid prosecution for a crime or to avoid giving testimony in a criminal proceeding. The change makes it possible for someone with an outstanding warrant who would have previously been prohibited from buying a firearm to obtain one, unless barred for some other reason.

According to the administration official, the decision to change the definition took place late last year under the Obama administration, after a review by the Justice Department's Office of Legal Counsel, but it was officially implemented under the Trump administration in February.

"The Justice Department is committed to working with law enforcement partners across the country to help ensure that all those who can legally be determined to be prohibited from receiving or possessing a firearm be included in federal criminal databases," a Justice Department official told CNN.

The Washington Post first reported the purge of names.

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