The Safe House - Nicci French Penguin

The Safe House is a scintillating psychological thriller by the Top Ten bestselling author, Nicci French
You open your home and your heart to a victim. But your house is anything but safe . . .
Samantha Laschen is a doctor specialising in post-traumatic stress disorder. She's moved to the coast to escape her problems and to be alone with her young daughter.
But now the police want her to take in Fiona Mackenzie, a girl whose parents have been savagely murdered. Yet by allowing Fiona in, Sam is exposing herself - and her daughter - to risks she couldn't possibly have imagined . . .