The Baltimore Police Department plans to require officers to scan their fingerprints at the start and end of shifts in order to prove they’ve worked the hours claimed on their pay slips.

The move comes as the department struggles to control ongoing overtime spending of nearly a million dollars a week, and amid the ongoing federal trial of two Gun Trace Task Force officers whose colleagues have admitted to rampant overtime fraud by the unit.

“Let’s not sugarcoat this: Criminals found a gap in the system and took full advantage of it,” T.J. Smith, a department spokesman, told the Baltimore Sun Wednesday. “That’s not fair to the city, and it’s not fair to the men and women in this agency who do their job honorably every day.”

Smith said the department is in the early phases of implementing the new biometric technology. Officials have purchased some hardware, but do not have an estimate for when officers will begin using it or how much the system will cost.