WARNING: A form of identity theft you need to know about

It’s the fastest growing form of identity theft.

You swipe your credit card or give it to a waiter, and within minutes someone is stealing from your account. it's called "skimming,” and on Thursday, dozens of law enforcement officials gathered in Naperville to learn more about how it's being done and how to stop it.

Call it ‘Skimming School,’ where around 50 cops learned about the latest technology the bad guys are using to steal your hard earned money.

"It is the fastest growing crime we are seeing. And every day it seems there are new methods being used to steal other people's identity and finances,” said Mark Sullivan of the FBI.

And just like school, there's show and tell.

"These skimmers, they can be installed inside a point of sale terminal or they can use it handheld like this...all they have to do is take your card, swipe it like this, and they've captured the magnetic stripe data,” said Paige Hanson of Lifelock Identity Theft Education.

The skimmers are getting smaller and cheaper, and spending just 40 bucks online will allow you to store a thousand credit cards.

"The easier it becomes for the criminal to obtain devices like these that can yield them large quantities of cash or purchases, it's something that's scary to us in law enforcement,” said Commander Jason Arres of Naperville Police.

The newest technology takes it a step further, allowing thieves to skim a credit card and then instantly duplicate that data onto a blank card. The stolen information is also captured on a computer.

“And now it's been duplicated successfully, so now if I wanted to get gas, groceries, go to the store, I could take this card just as I could this card,” Hanson said.

And police say they're finding more and more of these skim devices planted inside gas pumps and ATMs.

So, how can you avoid being skimmed? Use cash whenever possible, try to keep an eye on your card when you give it to servers or salespeople, and most importantly set up text notifications when your card is used and constantly check your account balances.

"They almost have to watch on a daily basis to make sure there are no compromises,” Sullivan added.

Skimmers often work hand in hand with people in the service industry, supplying them with the equipment and paying them anywhere from five to 25-bucks per card they're able to skim, which is why police urge employers to do thorough background checks when hiring new workers.

If you think your card may have been compromised, call your credit card company immediately and your local police.