IOWA CITY (AP) — An Iowa agency granted professional licenses to more than 5,800 private security workers without conducting mandatory criminal background checks, including at least two dozen who had records that should have disqualified them, auditors said Thursday.

Ineligible applicants received licenses to work as private investigators, bail enforcement officers and security guards because an Iowa Department of Public Safety employee failed to ensure that they passed national background checks, as required, state auditors found.

Since the problems were discovered a year ago, the department has revoked about 25 licenses that were granted to people who had felony or aggravated misdemeanor convictions that should have disqualified them under Iowa law, Commissioner Stephan Bayens said.

Nearly 600 other current license holders still haven’t undergone FBI background checks, and the department is working to get those completed in coming months, he said at a news conference. Thousands of others were granted licenses without proper scrutiny but have since passed background checks.