MONTGOMERY COUNTY, Va. – Authorities are investigating the possibility of a card skimmer being placed on a National Bank ATM.

The Montgomery County Sheriff's Office is warning National Bank of Blacksburg customers to check their accounts.

This comes after the bank has been dealing with multiple fraudulent withdrawals on debit card accounts from Radford to Johnson City, Tennessee, according to the Sheriff's Office.

The Sheriff's Office says there's a possibility that a skimmer was placed on one of the bank's ATM's, but the location of the possible skimmer is unknown.

The suspects have been blacking out camera lenses with a sharpie or by placing duct tape over them.

Authorities believe they may be using a midsize, black SUV.

The Sheriff's Office is also receiving reports of customers with other banking institutions in the New River Valley reporting fraudulent transactions on their accounts.

If you've recently used a debit or credit card in Montgomery County, the Sheriff's Office advises you to check your account records. It is still unknown where the skimming device could have been placed to acquire the banking information.

If you see someone suspicious around an ATM or notice suspicious activity on your account, please call NRV911 at 540-382-4343.