BALTIMORE (WJZ) — Baltimore Police Commissioner Michael Harrison told WJZ he welcomes a thorough review of hiring practices following a faulty background check that led to a man with prior gun charges, who was also a person of interest in a homicide, being hired for a top financial job in the department.

The mayor has already ordered a thorough investigation into how this employee slipped through the cracks.

READ MORE: Maryland Weather: Cooling Down

Thursday, the commissioner provided few new details but said he is determined to get to the bottom of what has become an embarrassing scandal. “What I don’t want to do is compromise any investigations, and I don’t want to compromise this individual,” Harrison said outside the federal courthouse.

Commissioner Harrison has yet to detail the breakdown in his department’s hiring practices that allowed Dana Hayes, Jr., who was listed on the city’s gun registry, to briefly become the BPD’s chief of fiscal services. He held that job for eight days before being fired Tuesday when his background came to light.

“Look, what happened happened,” the commissioner said. “It was brought to our attention. It was missed because of technology and there’s a human element to work with technology.”

The mayor told WJZ he has ordered “a comprehensive review of BPD’s civilian hiring practices” and “recommendations to improve their policies and procedures.” He also called it a “systems failure.”

“We welcome that,” Commissioner Harrison said. “We invite that to make sure we can look at the technology and the human part of it and they’ll make recommendations, and we will make whatever corrections necessary to include holding persons accountable.”

In a department-wide message WJZ obtained Thursday, Harrison said he is working with Scott and Quinton Herbert, the city’s director of the Department of Human Resources, to review how the department conducts the hiring process, including the background investigations that failed to flag Hayes’ past gun arrests.

Civilian hiring practices are under a microscope as the department is hundreds of officers short and pushing one of the nation’s first-ever programs to hire civilians to investigate low-level crimes, to take stress off sworn officers.

READ MORE: Maryland Weather: A Cold Front Sweeps In As Severe Thunderstorm Watch Ends

“To free up our police officers to focus on violence and not continuously focus on paperwork,“ the mayor said last week.

The city council still must approve the plan to use civilian investigators. The mayor is budgeting for more than 30 of them.

WJZ has tried repeatedly to reach Hayes, but we were unable to get in touch with him. His past weapons charges reportedly involve a gun stolen from Pennsylvania, but a representative for the state’s attorney told WJZ they were expunged, are no longer publicly available and illegal to share.

The commissioner has not said why that would disqualify Hayes or provided details about the homicide in which Hayes is a person of interest.

“What we did when we found out was swift, decisive action. I terminated the employee right away,” Commissioner Harrison said.

Harrison also wrote an email to officers saying “corrective measures” are being put into place to “ensure this does not happen again.”

The mayor and commissioner have not provided a timetable on when the investigation into hiring practices will be completed.

MORE NEWS: Waterfront Partnership Of Baltimore Offers Free Exercise Classes Along Inner Harbor