A warning to all Milwaukee residents, check your credit card accounts. Police say a credit card skimmer was found at an ATM at a Walmart on Layton Street in Greenfield.

Police were able to spot it after a victim's account was compromised.

The skimmer and a camera used to capture pin numbers are both in evidence now.

Greenfield Police have made two arrests after spotting the men they think are responsible on surveillance.

Officers say both suspects came into the country last month from Venezuela using work visas.

Greenfield Police Chief David Patrick says criminals are making it much harder to spot the skimming devices.

"And once they have that data they just put the information onto a gift card, so you can use it as normal, but as far as protecting your PIN, a lot of people will cover the area directly above the PIN with their hand, so you can't see it if there is a camera over," said Patrick.

Greenfield Police say it's a good idea to check your accounts every so often, and they advise you to set up alerts on your phone to let you know of any questionable activity on your account.