The Shape of Darkness / Laura Purcell.

Silhouette artist Agnes is struggling to keep her business afloat. Still recovering from a serious illness herself, making enough money to support her elderly mother and her orphaned nephew Cedric has never been easy, but then one of her clients is murdered shortly after sitting for Agnes, and then another, and another... Desperately seeking an answer, Agnes approaches Pearl, a child spirit medium lodging in Bath with her older half-sister and her ailing father, hoping that if Pearl can make contact with those who died, they might reveal who killed them. But Agnes and Pearl quickly discover that instead they may have opened the door to something that they can never put back... What secrets lie hidden in the darkness?[Bokinfo]