Federal authorities will re-investigate dozens of Syrian refugees living in the United States with potential criminal pasts who slipped through the cracks of the vetting system.

Two federal law enforcement officials told the Los Angeles Times that authorities will be investigating the refugee slip-up after the vetting system experienced a glitch and allowed dozens of refugees into the U.S. without being properly reviewed:

Agents have not concluded that any of the refugees should have been rejected for entry, but the apparent glitch — which was discovered in late 2015 and corrected last year — prevented U.S. officials who conducted background checks on the refugees from learning about possible “derogatory” information about them, the two officials said. At a minimum, the intelligence would have triggered further investigation that could have led some asylum applications to be rejected.

The refugees whose cases are under review include one who failed a polygraph test when he applied to work at a U.S. military installation overseas and another who may have been in communication with an Islamic State leader, according to the officials, who spoke on condition of anonymity because they were not authorized to discuss the matter.

The federal authorities speaking to the LA Times said they were using caution during the process and said that a refugee could have been in contact with an Islamic State leader without ever knowing that individuals’ affiliation with the terrorist organization.

As Breitbart News reported, President Trump is expected to sign an executive order barring refugees from countries such as Syria, Iraq, Iran, Somalia, Sudan and Yemen.

John Binder is a contributor for Breitbart Texas. Follow him on Twitter at @JxhnBinder.