"An End in Bath," by Janet Laurence, in Motives for Murder, edited by Martin Edwards, Crippen and Landru, 2017.
Irene Wootten lives a peaceful, quiet life in Bath, ever since her father died. One day an extroverted young man arrives, informs her that he is her cousin Rod from Australia, and he wants to stay for a while. Rather disturbing, but she enjoys his company.
More disturbing is the fact that Rod feels his side of the family was cheated out of their inheritance by Irene's father. And worse is her discovery of the assorted crimes that led to Rod's grandfather being pushed off to Australia. Is this a man she can, or should trust?
There is a lot more to this complicated and enjoyable tale of family intrigue.