By Kelly Werthmann

JEFFERSON COUNTY, Colo. (CBS4)– Investigators in Jefferson County are looking into a rise of counterfeit money cases.

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Twisted Sammie, a locally owned sandwich shop in Littleton, had customers use bogus multiple $20 bills at least twice in November and December 2016.

“I was pretty surprised, pretty disappointed,” store owner Curtis, who asked CBS4 not to use his last name, said.

(credit: Jeffco Sheriff)

(credit: Jeffco Sheriff)

Curtis didn’t realize the money was fake until he went to deposit the cash at his bank. When he found more fake bills a couple days later, he was able to pinpoint which customers used the fake cash on surveillance video.

“They’re the ones who handed over the 20s to us,” Curtis said of the images he shared with the Jefferson County Sheriff’s Office.

Two people have been accused of using fake money at the Twisted Sammie in Jefferson County (credit: Jefferson County)

Two people have been accused of using fake money at the Twisted Sammie in Jefferson County (credit: Jefferson County)

More than $100 in bogus bills were used at the sandwich shop, hitting the small business hard.

“It’s not just the fake 20s you receive, it’s the customer who’s getting change in real money,” Curtis said. “So you’re losing that twenty plus the change and it’s a compounding effect.”

(credit: Jeffco Sheriff)

(credit: Jeffco Sheriff)

Around the same time Twisted Sammie was paid with forged money, counterfeit bills were also used at Zumiez at the Southwest Plaza Mall. Authorizes believe the man and woman seen in security photos paid with the fake cash.

Investigator Terry Naes with the Jefferson County Sheriff’s Office said it is possible the customers in these cases may not realize they’re paying with forged bills. However, detectives still want to track them down.

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CBS4's Kelly Werthmann interviews Terry Naes with the Jefferson County Sheriff's Office (credit: CBS)

CBS4’s Kelly Werthmann interviews Terry Naes with the Jefferson County Sheriff’s Office (credit: CBS)

“If we can identify those people, our first question is, ‘Where did you get the money?’” Naes told CBS4’s Kelly Werthmann.

It is a question Jeffco investigators are asking more often. Counterfeit cash cases have more than quadrupled in Jefferson County in certain months. In November and December 2015, there were two reported cases each month. That number jumped to 14 in both November and December of 2016.

“We see a lot of people around the Christmas holiday who are using Craigslist, exchange cash, and may not even know they’re getting forged money,” Naes said.

(credit: secretservice.gov)

(credit: secretservice.gov)

Investigator told CBS4 they have not found anyone printing the bogus bills, but have several cases of people using the fake cash.

“We will keep trying to track down every lead until we can find people making the fake money,” Naes said.

Curtis said he is showing his employees how to spot forged cash by looking for the watermarks and serial numbers on bills. He is also warning other business owners to be on the lookout.

“Just be mindful,” he said. “I don’t know if you can always catch it, but you can certainly try to avoid it.”

For more information on how to spot fake money, visit: https://uscurrency.gov/

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Kelly Werthmann joined the CBS4 team in 2012 as the morning reporter, covering national stories like the Aurora Theater Shooting and devastating Colorado wildfires. She now anchors CBS4 Weekend Morning News and reports during the week. Connect with her on Facebook or Twitter @KellyCBS4.