*** The Good Nurse by Charles Graeber

The Good Nurse: A True Story of Medicine, Madness, and Murder is the mind-boggling story of Charles Cullen, a nurse who killed dozens of patients, usually by injecting them with various drugs, and who was not found out for many years, although the hospitals where he worked developed serious suspicions about his work, and in several cases were quite certain that he had killed patients, but simply discharged him without reporting his actions or even providing outright bad references for him. Only half of the book is about the murders themselves; the second half describes the tortuous police investigation, with no bodies and very few tangible clues — and major obstructions on the part of the hospital, which seems more concerned with protecting itself from lawsuit than pursuing the matter.

Do not read this before going into the hospital: it is that creepy.