When a Company or a Consultancy, looks only for a particular individual... irrespective of whether they know that person or no is called "Headhunting".
Let me know if there is any further information you would need, do get back to me.
If you are knowledgeable about any fact, resource or experience related to this topic - please add your views. For articles and copyrighted material please only cite the original source link. Each contribution will make this page a resource useful for everyone. Join To Contribute