With one more weekend to go to seal the deal on summer 2011, Ocean City is warning visitors not to get scammed on vacation rentals.

Ocean City Police said they recently received two complaints involving promised vacation rentals that were paid for in advance and turned out to be a scam.

Both of the victims were using Craigslist.com to find rentals in Ocean City and in both cases, paid several hundred dollars for rentals that did not exist.

Police are investigating but said they believe the perpetrators of the internet scam to be from outside the United States, leaving recovery of any lost funds unlikely.

Vacationers seeking rentals should take precautions against such scams, where scammers pose as property owners online. Police said users should watch for some red flags, such as poor grammar and punctuation in the ad, a reluctance to provide photographs, a lack of description of the amenities, or an unwillingness to accept a credit card or personal check for payment.

Renters should never wire money to a suspected landlord and must make sure the person renting the house actually owns it. Also, verify where you will pick up the key and who will provide it. Make sure the location and the person are real.

"Finally, if you have any suspicious concerns, follow your instinct," police said.  "Even if you have to pay a fee, you are often safer dealing with a licensed real estate agent."