Amy Duggan "Sister" Archer-Gilligan (October 31, 1873 – April 23, 1962) was a nursing home proprietor and serial killer from Windsor, Connecticut. She murdered at least five people by poisoning them. One of her victims was her second husband, Michael Gilligan; the others were residents of her nursing home.
It is possible that Archer-Gilligan was involved in more deaths. The authorities counted 48 deaths in her nursing home, the "Archer Home for the Elderly and Infirm."
The case attracted wide publicity at the time and has been cited as an inspiration for the play Arsenic and Old Lace and for Frank Capra's later film of the same name.
Between 1907 and 1917, in Windsor, Connecticut, nursing home proprietor Amy Archer-Gilligan purchased life insurance policies on her elderly residents before poisoning them with arsenic.