ITHACA, N.Y. (WHCU) – Authorities are cautioning shoppers to remain vigilant as a credit card skimming crime spree expands.

WSYR-TV reports say the total number of Walmart stores where credit card skimming machines have been recently found has risen to 16. They now include Ithaca, Geneva, Johnson City, and two stores in the state of Maine among others. The same three suspects (pictured below) are thought to be responsible for each crime. The machines were installed between July 2 and July 5.

Police recommend keeping an eye on your account activity if you shopped at these stores.