Hercue Poirot in Murder Hunt

With a strict regiment Mrs Boyten rules over her daughter and her stepchildren. One day she is death.
All believe in heart failure but Hercule Poirot, the diagnosis murder.
Who could be the killer?
The 24jähriege Raymond Boyton, his sister Carol, Miss Sarah King who is in love with Raymond, or at least someone else entirely?
Klaus Dittmann manages the Crime Life breathe it:
One can imagine the Murder Hunt in the head figuratively.
A very good thriller, read fantastic.