I do believe the ebook was avove the age of some thing published by Mary C
S636: Sister is reincarnated missing sister Author name may start with something after “Keene”; prior to 1993, likelier from 80’s or 70’s or before. It starts with a teen or young adult female driving her mother to a morgue in a small car (maybe a toyota) in the rain. They were going to look at a body that might have been the sister to the young adult woman. The sister, who ed Molly or Emily, vanished when she was only a little child and had been out playing with her kitten, and she vanished before the young adult sister was even born. …