Who to send probate letters to?

[Orest Omeliach]

I have my list of probates and I am unsure of who to mail them to. Should I mail it to the deceased's mailing address or should I mail it to the beneficiary/fiduciary. What is less offensive? I can act as if I don't know that the person passed away. If i mail it to the latter, should I show sympathy and send my condolences or should I get straight to the point?