The Shape of Night by Tess Gerritsen

A woman trying to outrun her past is drawn to a coastal village in Maine—and to a string of unsolved murders—in this novel of romance and psychological suspense from New York Times bestselling author Tess Gerritsen.
After an unspeakable tragedy in Boston, Ava Collette flees to a remote village in Maine, where she rents an old house named Brodie's Watch.
In that isolated seaside mansion, Ava finally feels at peace . . . until she glimpses the long-dead sea captain who still resides there.
Rumor has it that Captain Jeremiah Brodie has haunted the house for more than a century. One night, Ava confronts an apparition, who feels all too real, and who welcomes her into his world—and into his arms. Even as Ava questions her own sanity, she eagerly looks forward to the captain's ghostly visits. But she soon learns that the house...