Published: Aug 31, 2010 10:38 PM EDT
Updated: Aug 31, 2010 1:46 PM EDT

COLLIER COUNTY, Fla. - The Collier County Sheriff's Office is cautioning people to be vigilant after a card skimming device was discovered at an automated teller machine at a North Naples bank over the weekend.

The skimmer was found on the walk-up ATM at the SunTrust bank branch at 2420 Vanderbilt Beach Road by a customer who attempted to use the machine, located at the bank's front entrance, around 9 a.m. Sunday.

Criminals attach these fraudulent devices to cash machines in a bid to steal and ultimately clone customer bank card data.

The customer told CCSO detectives that his debit card did not slide properly into the card reader. He pulled on the card reader, becoming suspicious that it had been tampered with, detectives said.

The card reader then came unattached from the ATM to reveal that it was a skimming device placed over the original card reader, detectives said.

The customer took the device home and returned to the bank with it on Monday to report the incident. Bank officials then contacted CCSO.

Detectives attempted to locate the ATM camera used for capturing card personal identification numbers as they are entered on the key pad. Further investigation revealed that all of the screws had been removed from the light fixture, which is a common location for placing the mini DVR camera. No camera was found.

Detectives believe the person who placed the device on the ATM returned to the machine and recovered the camera before the incident was reported.

Further investigation by detectives revealed the device was placed on the ATM on Saturday around 8:10 a.m.

Detectives said it is unknown at this point whether anyone's credit or debit information was compromised before the skimmer was found.

Anyone with information is asked to call the Collier County Sheriff's Office at 239.252.9300.

Keeping an eye out for hidden equipment at cash machines is a good idea, detectives say. The Collier County Sheriff's Office offers these tips for spotting these devices:

Be aware of your surroundings. Be extra careful of machines in dark places or in areas that do not appear to be well guarded and monitored.

Pay attention to the front of machines. If it looks different from others in the area (for example, it has an extra mirror on the face), has sticky residue on it (potentially from a device attached to it), or extra signage, use a different machine and notify bank management of your concerns.

Notice how it feels to type in your PIN code. If it's difficult for you to punch the keys, or you feel resistance, it could mean that a key pad overlay is present.

Cover your hand as you type in your pin. If a camera is present, or someone is trying to look over your shoulder, this will obstruct their view.

If you think the area around the card entry slot looks peculiar, pull on it. If it comes off or loosens, notify the Collier County Sheriff's Office immediately, but try to leave the machine as you found it. Leaving the evidence in place could help deputies track down the criminal.