Thriller book from the 80’s or 90’s
I’m trying to find a book I read when I was 16 in a class. It follows three points of view, the killer/kidnapper, an investigator and a victim. At some point in the book, the killer assassinates a woman (not the victim that we see the point of view of) with a scarf, he strangles her with it, I’m pretty sure. The killer lives in a secret room in a mall or similar place where he works, pretty sure he’s janitor or something like that. He abducts a young woman (the victim we see the point of view of) and a young boy and sequesters them in said secret room. Pretty sure the young woman has a blindfold on, but not the young boy. Pretty sure the killer has a bomb too. The author is a woman, known for writing books about violent things happening to women (abductions, hostage situations, etc.).