Be careful with those security numbers on the back of your credit card.

They are just as important as the numbers on the front of the card.

Do not give out those numbers to just anyone because doing so could cost plenty, according to Deputy Capt. Dan Caddell of the Bee County Sheriff’s Office.

Caddell was talking this week about a new phone scam being tried by swindlers anxious to get to your credit card account and leave you in debt.

Caddell referred to a recent e-mail warning that people have been receiving, apparently from people who have been victimized by the new scam.

“One of our employees was called on Wednesday from VISA and I was called on Thursday from MasterCard,” the warning said.

According to the warning, the caller poses as an investigator of the credit card company who warns that a suspected illegal purchase has been made on the account. After the intended victim reports that he or she did not make any such purchase, the caller promises a credit on the account.

The scammers never ask for the credit card number. They already have it.

Then the “investigator” claims that the company wants to give the victim a credit for the purchase so he or she will not have to pay the bill.

But to properly give the intended the credit, the victim must provide some information.

That information means that the caller wants the victim to read off the seven numbers on the back of the card. The first four numbers are part of the credit card number. But the next three numbers are security numbers that allow you to verify that you do, indeed, have the card.

“That’s correct,” the bogus investigator tells the victim. “I just needed to verify that the card has not been lost or stolen and that you still have your card.”

Anyone who has made a credit card purchase over the Internet has had to provide that number over the secure billing lines of the company with which he or she is doing business. Being able to provide that number proves that the person making the order actually has the card.

“You actually say very little,” the e-mailer warned. “They never ask for your card number... But after we were called on Wednesday, we called back within 20 minutes to ask a question. Are we glad we did! The REAL VISA security department told us it was a scam and in the last 15 minutes a purchase of $497.99 was charged to our card.”

The victim in that case was able to stop the charge, cancel the account and open another one, with new numbers on a new card.

VISA officials said they never ask for numbers from one’s card. They already know the numbers.

Caddell agreed. “If they’re legitimate, they’ve already got those numbers.”

People should never give out credit card or bank account information over the phone if they are contacted by someone, Caddell said.

“The best thing you can do if someone calls you looking for information like that is ask them for a phone number so you can call them back. If they won’t give you a phone number, then you’ve got a problem,” Caddell said.