I can remember Mma Ramotswe using the term "late". She may have used "passed" as well, but "late" is the one I remember better, if so. I agree: the television series was good, too.
A good reminder: I'm fairly systematically (and as rapidly as I can) re-reading all the authors I've enjoyed in my life: Jane Austen, Donna Leon, Dorothy L Sayers, P.M. Hubbard, John le Carré, Ngaio Marsh, and just started on P.D. James.
Alexander McCall-Smith will be a good one to turn to next.