Angel of Mercy (serial killer)

Angel of mercy is a rare type of serial killer who is usually female, and employed as a caretaker. The angel of mercy is often in a position of power and decides the victim would be better off if they no longer suffered. This person then uses their knowledge to manufacture the death of her/his victim. As time goes on, this behavior escalates to encapsulate the healthy and the easily treated.

One known serial killer that does seem to fit this description is Jane Toppan. As a nurse she would derive pleasure by saving the lives of her patients after bringing them to the brink of death through drug induced comas. Soon afterwards she found she derived more pleasure in their deaths.

In literature

"Arsenic and Old Lace" is a play by American playwright Joseph Kesselring with the two main characters, the spinster aunts, being the angel of mercy for lonely old men, whom they relieve of their misery by poisoning them with a glass of wine laced with arsenic.

The character Annie Wilkes in Stephen King's novel, Misery, seems to be a serial killer of this type.

The 'angel of mercy' is mentioned in Agatha Christie's By the Pricking of My Thumbs. It is also mentioned in a "Fear Factory" song "Demanufacture".