This quest is not available in game.
Search through the packed up possessions for a clue.
My father was the caretaker of the estate long before I was. He had to mop the blood up after the massacre. But that's neither here nor there.
The last funds of the Flintridge trust have dried up. Now the last of the family possessions are headed for auction. Blame the tax vultures. I guess if you're really itching to learn more you're free to look through this junk. Who knows what you might find.