It is. I had a guy from UK did the same scam. It works like this

He will send you a large amount of casher's check, and ask you refund the balance. You can deposit the check. only one month later, your bank will tell you the check would be bad check. The bank will debit the amount plus penalty, while your real check is cashed by him, and you will never get your money back. I still kept the bad check. I can show you if you are interested.