Book about a shapeshifter hunting the women of a family

Question

At some point in the last ~3 years I've read a book about a family trying to escape from a shapehifter who was hunting the women of that family for generations. The book was written in different timelines so that you would get to know the female main character, as well as her mother and the antagonist over the course of the book. I will try to present the three story aspects I remember without switching between them.

It started in our current time with a family trying to escape from something in their car on their way to a safehouse in the mountains. The father is heavily wounded and the little daughter in sleeping in the back of the car while the mother is driving. They meet with an old friend of her late father who is helping by patching up the father. Her late father died recently, which was the beginning of the chase and later the shapeshifter appears in the form of her late father trying to bring her out of her safehouse. The shapehifter kills the father but the in the end the mother manages to kill the shapeshifter, which is the Happy End.

The protagonists mothers timeline is written from the perspective of the protagonists father. He is an academic and meets a woman in the library and after some quarrels they fall in love. She later tells him that there is a shapeshifter haunting her family for several generations, always eliminating the people closest to the women to be with them at some point. He doesn't believe her, but later they settle down. But he makes a mistake when he is publishing a book with his and her name in it. This allows the shapehifter to find them.

This is one of the scenes I remember most vividly, though I am missing the exact details and am merely trying to convey the style of the scene. She is alone at home and her husband comes back from work. They talk about their day and have sex, but then she says that he asks about the books on her nightstand. A harmless question, but those books contain the information her family wrote down over the last generations about the shapeshifter and are an incredibly important aspect of her life. There is no way her husband could have forgotten about them. So she slowly gets up like nothing happened and says that she wants to make coffee. Her husband hates coffee. And says he'd love a cup.

So she goes down and continues asking questions about whether he picked up the car from the mechanic. Her husband answers that he didn't manage to do that today. Sadly they didn't have a car. After a few questions he comes close to her and she throws the coffee at the shapeshifter. They get into a fight and he ties her to a chair. He goes searching through the house and finds a picture of her daughter. As she won't tell him anything about her family he kills her in a very brutal way. Something like putting his hands to her head and through magic making her ears and eyes basically explode.

When her real husband returns he sees her in the chair and immediately calls his daughter in school for their personal emergency drill. This scene was very heartbreaking. Basically:

Father: "Do you need anything? We won't be able to come back."
Daughter: "Only you and mommy."

The origin of the shapeshifter begins in eastern Europe, while the rest of the book is in America. The shapeshifter is from a family of shapeshifters but was some kind of outsider for some reason. When he was supposed to start being the heir of his father he decided to go drinking with normal people instead of being on the ball. He drinks with a guy and a girl and falls in love with the girl. To get her he kills the guy and shapehifts into his form. She realizes this and this is basically the beginning of him haunting her family. Always trying to find her and replace someone who is close to her.

I would like to read this book again. Can you help me remember what the name of this book is?

Answer 1

String Diaries by Stephen Ljoyd Jones

A family is hunted by a centuries-old monster: a man with a relentless obsession who can take on any identity.

The String Diaries opens with Hannah frantically driving through the night--her daughter asleep in the back, her husband bleeding out in the seat beside her. In the trunk of the car rests a cache of diaries dating back 200 years, tied and retied with strings through generations. The diaries carry the rules for survival that have been handed down from mother to daughter since the 19th century. But how can Hannah escape an enemy with the ability to look and sound like the people she loves?
Stephen Lloyd Jones's debut novel is a sweeping thriller that extends from the present day, to Oxford in the 1970s, to Hungary at the turn of the 19th century, all tracing back to a man from an ancient royal family with a consuming passion--a boy who can change his shape, insert himself into the intimate lives of his victims, and destroy them.
If Hannah fails to end the chase now, her daughter is next in line. Only Hannah can decide how much she is willing to sacrifice to finally put a centuries-old curse to rest.

The books I remembered from the scene where the shapechanger finds Hannah's mother were the String Diaries, which is why they were so important that her husband couldn't possibly have forgotten them.

Here is the blurb on the back of the book:

He has a face you love
A voice you trust
to survive you must kill him

The rules of survival are handed down from mother to daughter. Inherited, like the curse that has stalked Hannah and her family across centuries.

He changes his appearance at will, speaks with a stolen voice and hides behind the face of a beloved, waiting to strike.

Generation after generation, he has destroyed them. And all they could do was run.

Until now.

Now, it is time for Hannah to turn and fight.