A very famous celebrity, now deceased (a few years ago) wrote a passionate love letter to her equally famous husband, also now deceased, while they were leasing a home during the filming of a movie in the 1970s. Long after the couple left the home, the letter was found under the bed by the home's owner, who has kept the letter all this time but wishes to sell it.
1. Who actually owns the letter: the possessor, or the celebrity's estate?
2. Is selling the letter itself—which may involve publishing it on a dealer's website or in a catalog—a violation of any US laws?
3. Are there other considerations one should be aware of?