Two homeless mentions in Kill Switch by Neal Baer and Johnathan Greene.
One was a shopping cart homeless woman who may have witnessed a murder; more likely she stole a dead woman's jewelry. The other was when Dr. Claire Waters was a first-year psych resident being hazed by nurses who assured her that it was part of her job to bathe delusional homeless patients.
Dr. Waters is a forensic psychiatrist with a past she wanted to forget. Might say Kill Switch is two mystery tales told in one story. Perhaps that is why I got bogged down in reading, somewhere past the middle of the novel, even though, at 289 pages, it was not a long book. I was puzzled at the end of the novel, wondering who was responsible for the first killing, if not the serial killer.