Who Owns The Rights? Most Likely Not Them
My two cents on who owns the rights.
When an artist creates a piece, he/she owns the rights to said piece. Once purchased, the artist still retains the rights, unless otherwise specified "” even though a collector owns the original.
Upon death, the estate or whomever the artist bequeathed the rights to owns the rights.
Here's one catch with this work, that could be interesting. If a piece of art is created as work for hire, in other words, somebody paid the artist to do the work, the lines get blurred, and may be owned by the party who hired the artist; depending upon what deal was struck between artist and employer/buyer.
So, Black Sparrow, or whomever owns the rights to those titles/pieces now (Ecco?), may be the owner of the rights. Or, the estate, Mrs. Bukowski, etc.
Hope that makes sense.
Either way, these people most likely don't own/have the right(s), and are probably crooks.
Pax