Employee Bal Karti said the credit card machine was not working three days ago, so they put a sign up asking customers to pay inside.
A technician came out Thursday, discovered the skimming device on the machine, and immediately contacted West Hartford Police.
Police removed the device and surveillance video from the New Britain Ave. gas station.
It is unknown at this time how long the device was in place.
West Hartford Police are still looking for the person responsible.
"They don’t need to work, they get money from the others pockets, other people work for them" Karti said. "We are very upset, we are very sad hearing those things."
West Hartford Police said this issue is becoming more common throughout the state.
Police recommend you look for "safety stickers," which cover the lock on the pump. If they are torn, its likely the machine was tampered with.
There are several ways skimmers work including capturing the information through the actual machine which the crook would have to pick up, or they could collect through bluetooth.
West Hartford Police ask you pay attention to the exterior of the pumps and if you see anything unusual, to report it.
"I don’t use my card at pumps," customer Sarah Boudreau said. "I always go in the store, I try to stay safe with my card all the time."
It's common for criminals to install the skimmers when gas stations are closed, therefore police ask you pay attention to any activity at a gas station late at night.