Murder by an Aristocrat — Mignon G. Eberhart

From one of America's favorite writers: When a member of an aristocratic family takes a bullet, a nurse and amateur sleuth investigates (Mary Higgins Clark). Nurse Sarah Keate is no stranger to mystery. An intrepid redhead with a biting wit, Nurse Keate has solved conspiracies and murders in places as varied as her once-sleepy hospital ward, a gothic mansion, and the Sand Hills of Nebraska. But what she encounters with the Thatchers is a new breed of deadly. The Thatchers are as close to aristocracy as an American family can get, and one of their own requires Keate's care for a suspicious bullet wound to his right shouldera relative insists it was self-inflicted. When the convalescing man dies under even stranger circumstances, Keate knows that he was murdered. And what's worse, there is no doubt that the murderer resides in the Thatcher mansion. As the family closes rank and struggles to keep its darkest secrets buried, Nurse Keate will stop at nothing to find the truth.