NEW YORK (CBSNewYork) — Con artists with bogus bills are targeting victims at weekend yard sales in Staten Island.

CBS2’s Dave Carlin reported that counterfeiters and money launderers have begun creeping in during yard sales in Westerleigh.

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The scam artists have been unloading their fake big bills on cheap items, and getting real cash back.

“Then I felt, ‘Oh my gosh, we were victims.’ We were so innocent,” said Mary Ann de Francesco.

De Francesco held a block sale in Westerleigh with two other homeowners last week. All three were taken in by a chatty woman they’d never seen before, and she had at least one accomplice.

“It was some children’s clothes that she bought, supposedly for her daughter. It amounted to $10,” de Francesco explained. “She got 40 back from her 50, but then she did other people, too, and they were stuck with 20s and 50s, so altogether, in these three houses, it came to $200.”

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The fake $50 bill from the yard sale was brought to Staten Island Diner, and the cashier quickly figured out the bill was not real.

When marked with a pen, the fake 50 turned black. The ink on the bills should stay yellow when that happens.

“If you hold it up towards the light, you see Jackson’s right there. You see a watermark there that helps, too,” said Akis Iliopoulos, the owner of Staten Island Diner.

Police are working with federal investigators to try to find the suspect, who victims describe as short, heavy set, in her 40s with short brown hair.

De Francesco knows the chances of getting money back are slim to none, so at her next yard sale she will not accept $20 and $50 bills.

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Investigators are looking into whether the same suspects were at another Staten Island yard sale the weekend before last and unloaded fake money there, too.