ThanksYour question has likely already been answered perfectly. Also, something else came up for me when I saw your sentence and question:
If you're just describing the man who stole your bag, then my comment is less important right now. If you ever want to say that among multiple men, only one stole your bag, you might find this structure helpful:
-It was the tall man who stole my bag.
(Meaning: and not any of the other ones, short, fat, thin, hairy, bald, etc.).
Most of the time I find it less helpful to define grammar when learning how to use something. For me, multiple examples are better. But this thread also made me think of related grammar (and correct me if I'm wrong here, guys): restrictive and non-restrictive clauses.
-The man who was wearing a blue shirt stole my bag
(Meaning: Identifying/limiting, because we know that it was not the man who was wearing a green shirt.)
-The man, who was wearing a blue shirt, stole my bag
(Meaning: Additional/optional, because the important part is that a man stole the bag, and also he was wearing a blue shirt.)
Hasan, I interpreted your post without asking for clarification first. So I hope this added more than it distracted.