CHARLOTTE, N.C. - An increase in fraud cases is sparking concern over counterfeit money.

Right now, the Charlotte Mecklenburg Police Department is involved in several active investigations, including two cases with a combined $15,000 of fake cash and checks.

NBC Charlotte is looking into how you can tell if there is counterfeit money.

It comes just a few days after police arrested four people for financial fraud at an apartment on Hawthorne Lane. Police say they served a search and found evidence of manufacturing fake ID’s and bank documents.

“There were a whole bunch of cops over in the area,” says neighbor Todd Hoy.

CMPD is now dealing with an increase in financial fraud. In another case, police are investigating an incident at a grocery store on the 6100 block of the Plaza involving suspects stealing, altering, and cashing about $6,000 worth of checks. In addition, another police report shows more than $9,000 of counterfeit cash at an ATM.

“I would hope I wouldn’t come across it because I wouldn’t know the difference,” says one man.

NBC Charlotte is looking into the signs to help you identify counterfeit money: Look out for blurry borders, broken presidential portraits, or missing watermarks. Also, pay attention to red and blue hairs in real money, as well as a security strip visible under UV light.

Earlier this year, police say a guy was caught on camera trying to pass a fake $100 bill in Stanley. Before that, counterfeit cash was seized in Rock Hill. Last spring, three suspects used $1,500 worth of fake money at Belk in Gastonia.

“I think it’s unfortunate that people were doing this to try to take advantage of people,” says one man.

“I work hard for my living and do it the right way,” says Hoy.

The four people were arrested without incident at the apartment complex. Police also recovered guns, ammunition, and $500 worth of marijuana. They are facing multiple charges.