Mr. Potter,
I wish to commend you for choosing Hogwarts as your adopted son's place of education. The students and teachers there are all very caring toward one another, and I find myself intrigued by the respect shown to werewolf rights in allowing the boy Randolph Edwards to attend. Unfortunately, this bond of trust can be misused, and it certainly has been. By me. When it is realized at the school that your son is missing, I'm sure they will inform you. However, I don't want to wait that long, so I thought I would inform you myself. But he's not really missing, after all. I have young Matthias. And you have only chance of getting the boy back.
You see, after all this time, my search for information has gotten me nowhere, with one exception: everyone agrees that you have the knowledge I seek. So, as a matter of simple expediency, I have kidnapped your child, and will hold him hostage until you tell me how to divide my soul as The Great Lord did. I desire immortality, and I will have it. If you do not wish to help me attain this, your son will die. I will personally cut open his throat and watch the light leave those beautiful blue eyes. If this is not enough to persuade you, I may be forced to move on to your other two children, dear little Sirius and Charlotte . . . or would your lovely wife, Ginevra, be more convincing to you?
As I said, Mr. Potter, you have only one option. You give me the information. I will not negotiate with you. When I have the information, I will tell you where to find your son. I will send an emissary who will collect your answer.
Most sincerely,
Thomas Tyrell