Ashes in An Urn — Jan Roffman

From the very first, Louise Makepeace felt that there was something strange - and evil - about Howard Croft, the charming young man who came one day to look at Aunt Emily's garden, and stayed on as the old lady's guest. Her feeling about Howard was based on pure instinct, until Aunt Emily became ill and refused to see her niece - or so Howard said....

It was impossible for Louise to sit by and watch murder being done, and even more impossible to get Aunt Emily, or anyone else, to believe that Howard's sunny smile hid a dangerous and devious mind.

And so Louise quietly poked, prodded and probed - and discovered one night that the evil force that was slowly but surely destroying Aunt Emily had transferred itself to her....