So recap for myself:
A man is founf murdered in thr apartment of a crazy woman who was taking care of him.

Apparently the man impersonated a dead guy and through date he stole from his last job he invades the lives of some of the richer clientele. He listens to them and fakes the same interests as they do. While doing so he takes their money.

We learn that he hides away a woman (Beth) who is his secret weapon. In the end she kills an old woman because he was able to make her change her will to his benefit. She was mentally ill and off her medicin.

Our Robert Poole got murdered by a brother amd sister who were smarter than him. She was a notary and he a financial advisor. They also killed one of his clients and were going to kill the woman who took care of Robert's dead body when they thought she knew too muck. Luckily they got arrested beforehand.

Frieda gets stabbed by Beth but survives only because Dean Reeve (first book) saves her life but only she knows it. He didn't want her to die because he wants to be her undoing.