Legal Question in Real Estate Law in Maryland

It may well be, depending on the circumstances. Falsely holding out that someone owns property s/he no longer owns and/or "selling" to a "buyer" when the seller has already sold to someone else amounts to both criminal and civil fraud. Without knowing more facts one cannot say whether a particular transaction is legit (it is possible to have contracts that terminate if another higher offer comes in, it is possible to sell interests in property to several people, so forth and so on).