Who is Miss Elizabeth Cole from Curtain and what is their importance?

Miss Cole is actually Elizabeth Litchfield, and the Litchfield case is one of the cases on Poirot's list. Her father was a rich tyrant, who kept a tight rein on his family, and when he mysteriously dies..... an investigation determines his death to be murder. Elizabeth's oldest sister, Maggie, confesses to her father's murderer, hoping that the rest of her siblings could enjoy their inheritance.