"This one is particularly nefarious because of that," Kelley explained.
Kelley said scammers are targeting the Denver metro area for a reason: "Because there's so many people moving here and because of the issues with pricing and availability," he said.
Sites like Trulia and Zillow make it easy to pull the scams off.
"They can find out who owns properties, they can get the photos," Kelley said.
Scammers then use the listing photos to post fake rental ads online, ask the renter to wire them the first month's rent but when they show up there's no key and no house for rent.
"A lot of them are overseas and out-of-state and how do you find them? Whatever money they've collected is going to be pretty hard to get back," Kelley said.
Kelley has these tips for how you can make sure you don't fall victim:
First, he said do your research.
Make sure the property management company or homeowner are legit. A property search can show if the person renting the house owns it.
Second, never rent a property without seeing it first.
"You wouldn't buy a car without driving it, or without looking inside," Kelley said.
Lastly, don't trust anyone who asks you to send them money in the mail.
"Unfortunately, the information is out in the public domain and that's is just a risk that we take doing business the way that we do," Kelley said. "The reason these scams happen is because people still fall for it."
Kelley said homeowners trying to sell their property who get caught up in one these rental scams should contact Craigslist or Zillow about the fake ads and they will usually take them down.