Orville Lynn Majors United States 1993 to 1995 6 130 LPN in Vermillion County Ind., Preyed on elderly patients—thought to have killed many of them with injections of potassium chloride. Sentenced to 360 years in Indiana.[318] Efren Saldivar United States 1989 to 1997 6 50+ Respiratory therapist who killed six patients, possibly as many as 120.[319] Christine Malèvre France 1998 and earlier 6 30 Nurse who killed terminally ill patients claiming that they had asked her to help them die, something denied by their families. Sentenced to 12 years in prison for six murders and suspect of 30.[320] Antoinette Scieri France 1924 to 1925 6 12+ Nurse who poisoned her elderly patients.