The Horn of Roland: Ellis Peters

A woman goes with her father back to his hometown where there seems to be an old buried secret. Lu, the father was a member of the resistance during WWII and was unable to save a friend. As soon as the pair get settled they receive a couple phone calls from a child of Valentine Gelder threatening to kill LU in revenge. The story plays out where the offspring of Gelder likes and respects Lu and the murder doesn't happen and the truth come out on what happened on that night when they find the witness to the events.