The Skin Beneath by Nairne Holtz

Five years ago, Sam O'Connor's sister Chloe died in New York - just another accidental overdose at the Chelsea Hotel. Now, someone has sent Sam a postcard telling her Choe's death was no accident. She died of a gunshot wound, not an overdose, while she was investigating a political conspiracy. 'Coincidence?' the postcard reads, 'Think about it...'
Sam tries not to think about it, but she has to find out why Chloe died. Every answer produces more questions as Sam steps into Chloe's life, retracing her last days in Montreal, Toronto, Detroit and New York. Along the way, Sam falls for the beautiful but troubled Romey, Chloe's last roommate, who knows far more than she's willing to tell. As Sam navigates the twisted trail between fact and fantasy, she is forced to confront some difficult truths about her sister and, more frighteningly, about herself

Nairne Holtz, a writer, librarian, and bibliographer, lives in Montreal. This is her first novel.