ABANDONED. Horror book about a boy reincarnated as a cat

[Kat]

I read this book around 1996 or so, and it was old then, though I can't really guess any better than that. The paperback cover was yellowed, with an ink drawing of a woman and a cat. What I can remember about the book (besides it terrifying 7 year old me) is that a woman started working at an animal shelter after the death of her young son. She notices one cat that has the same reddish hair and blue eyes as her son had, and she becomes convinced that the cat is her reincarnated son. SPOILER--I believe the woman ends up killing herself, hoping she will also be reincarnated as a cat, so she can join her son.

If anyone can tell me what this book is called or who wrote it, I will absolutely love you for solving a mystery that has nagged me for over a decade. Thank you!

[Lobstergirl, au gratin]

Kat, are you still looking for this book?

[Kat]

Lobstergirl wrote: "Kat, are you still looking for this book?"

Absolutely! It plagues me, and no one I know seems to have heard of it.

[Lobstergirl, au gratin]

Still looking?

[Tab]

Kat, do you remember anything else that happened in the book? Did the woman have other family members, friends, co-workers?

Does she adopt the cat, keep visiting it, etc?
Any other paranormal elements?

[Spencer1984]

If I remember correctly, her son disappears and is presumed dead for several years when she encounters the cat. She adopts it and begins to see more traits that convince her that this is her son, while losing her own humanity. A con man eventually appears and claims to be the lost son, and she believes him until she notices a flaw in his disguise (the lack of a limp and related orthopedic shoe?). I don't remember the full ending, but I thought she ended up killing the man and abandoning her humanity entirely. Unfortunately I can't remember the title or author, but I had read it around 1987 - 1989.

[Lobstergirl, au gratin]

Spencer1984, are you the same person as Kat? I'm noting that Kat read it around 1996, but you read it earlier.

[Spencer1984]

No, but I am also trying to find the title to this book and thought some additional information may help someone recognize it.

[Lobstergirl, au gratin]

Ok, thank you for clarifying.

[Crystal Dawn]

This may not help that much... but it makes me think of Fluke by James Herbert. Same premise, but a dog.

[Lobstergirl, au gratin]

Lobstergirl wrote: "Still looking?"

No reply in 4 years. Moving to Abandoned.