Henry County police released video of a man passing counterfeit cash, and in the video you can see how the clerk thinks it's 100 percent real.

At the McDonough GameStop, video shows a man pull out an envelope full of fake cash to pay for a game controller.

"How many times has he done this, we'll never know," Sgt. Joey Smith of the Henry County Police Department told Channel 2's Craig Lucie.

In the video, you can see the clerk hold the fake $100 bill up to the light. Then he does another check on the counter before placing it in the cash register and giving the man change in real dollar bills.

"We've seen hundreds, fifties and twenties," Smith said about the fake bills.

Conyers police recently arrested Allen Jermaine Johnson, 22, when they said he was spotted in three metro counties using counterfeit cash buying thousands of dollars in money orders.

Investigators said it's possible that it's Johnson in the recently released video captured in December, but they can't say for sure.

"We've been seeing a lot of $100 bills," Smith explained.

Investigators said there's still a lot of counterfeit cash floating around after they busted a $3 million counterfeit ring.

"Some of the forgeries are really good. Undetectable," Smith said.

Lucie went to a McDonough gas station where the cashier told him that he's seen how good the cash can be.

"If it's black, it's fake. Sometimes though we check with the pen and it's good," Parmindel Grewal told Lucie while showing off a counterfeit-detecting pen.

Grewal told Lucie the cash will pass the pen test because one $100 bill is printed on top of multiple five dollar bills to create the counterfeit money.

He said he's seen Abraham Lincoln's watermark picture inside a $100 dollar bill when it should be the watermark of Benjamin Franklin.

Police told Lucie that if anyone comes across fake cash they should call them at 770-288-8200 or take the money to the bank so they can verify it.

They said you should never just try and pass it because you could become part of a Secret Service investigation.