The typical renter scam on free websites , NOT for rent, the scammer took the agents pictures and posted as a rental. He will try to collect a deposit from a renter and then they will never hear back from him again. Sometimes they even break into the house to meet inside.
Unfortunately scammers find properties that are for sale, copy the photos, description, etc. and list them for rent usually on Craigslist but I guess now they are doing it on Trulia too. They then ask for a deposit and then they vanish. Did you hit the flag button on the listing to notify Trulia that's this rental is fraud?
If you are looking for a rental I suggest working with an agent. If not, never give anyone a deposit over the internet for a home.