A local couple thought the deal they got on a rental house in Renton was too good to be true. They were right.

Investigators now say they were victims of an elaborate scam.

In October last year Sean Stewart went to check on one of his rental properties and found a couple he didn't know living inside.

Mike and Lia Lester said they and another couple rented the house after seeing the home advertised on the Craigslist web site.

They met a man named John McCormick who claimed to be the landlord and paid him $5,700 in rent and security deposits and he gave them the keys.

But Sean Stewart, who owns the house, had never met McCormick or the Lesters. He had other renters ready to move in when he found the Lesters in his house.

That confusion led to a heated confrontation.

"Until the police are here you're not coming in my house!" Mike Lester said angrily from inside the house in October. He was yelling at Stewart's father, who had come to change the locks on the doors.

"We paid our rent, we've got receipts, we've got a lease -- what are we supposed to do?" Mike said at the time.

After a three-month investigation, King County sheriff's detectives just released a sketch of "John McCormick" -- the man they believe scammed the Lester's.

He's a white man, about 42 years old, 6'2" tall and about 195 pounds with a thin build and dark brown hair.

Investigators say he may be driving a gold or tan Mercury Cougar four-door sedan.

Anyone with information about the case is asked to call the sheriff's office.