D.C. police are warning residents about a spike in credit card readers used to steal information, otherwise known as skimmers, at retailers in the area.

Credit card skimming devices have been located by employees and removed from five establishments across the District from March 25 through April 12, according to D.C. police.

NBC Washington reported that all five locations were grocery stores.

“The keypad was sparkling, like brand new,” store employee John Perry-Miller told NBC Washington. Perry-Miller said he discovered one of the skimmers at the Safeway on Wisconsin Avenue in Georgetown.

The skimmer device can look identical to the keypad on the reader. But police said there are ways to be mindful before making your transaction.

• Police recommend comparing the machine you are using to the one next to you, checking the alignment of the card reader with the panel underneath and looking inside the reader before inserting your card.
• Police also said to make sure your device can’t be moved or budged when touched, and if you do suspect a card skimmer, to contact police immediately.

Images of two people believed to be connected to the skimmers were captured by nearby surveillance cameras, police said.