Follow The MoneyFinished another Sue Grafton ... this one was S is For Silence. Always have to look for a motive. In this case, there was a good sum of money to be absconded with, and someone one was willing to commit murder for the dough.
There were a number of suspects who were not well off, if not broke, and who would have seemed likely to have done the dirty deed, at first blush.
But instead it was a wealthy person who killed for the cash. I guess that happens more often than you think. They just can't ever get enough.