Investigators in Michigan said they found $100,000 in counterfeit cash at a home following a Facebook Marketplace purchase.

Lieutenant Rene Gonzalez with the Michigan State Police Brighton post said one sketchy transaction blew an alleged counterfeiter’s cover, and it was just the tip of the iceberg. He said the suspect bought a drone through Facebook Marketplace for $800 using counterfeit cash in late March.

“They met up at the victim’s residence. The transaction of the cash was completed, and the property (was) turned over to the suspect," Gonzalez said "The victim went back in the home and realized that the money that she was given was counterfeit. So, that’s when police were contacted.“

Detectives discovered that other law enforcement agencies in the state are investigating similar cases involving the same person. Details from each case helped them develop a suspect.

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While executing a search warrant on May 23rd, investigators said they also took a laptop and cell phones as evidence.

“This is the first we’ve heard of it, and we want to make sure others in the area are well aware," resident Matt F. told the Scripps News Group in Detroit.

So, how can people who do cash transactions protect themselves?

"There’s a lot of scammers out there, and Facebook is just another avenue for them to work off of," Gonzalez said. "So what I suggest to people, just like banks and stores use, if you give them a hundred dollars, they’re going to take a pen out and draw a line across that bill to ensure that it’s real.”

You can buy the pens at office supply stores or on Amazon. A dark line means it's fake. A gold or yellow line means it's authentic.

The Secret Service also has images and a detailed breakdown on its website of what real money looks like to the naked eye.

Know Your Money by WXYZ-TV Channel 7 Detroit

“There’s a lot of things people can look for," Gonzalez explained. "Cash now is gonna have a little thread right through it, a gold thread right through the one side of the money. The texture of it feels different. Make sure that the serial numbers are different. Like a lot of times, these counterfeiters don’t think, and they’re just printing out this money, and it has the same serial number throughout 10 bills, 20 bills.”

This story was originally published by Darren Cunningham with the Scripps News Group.