Amy Duggan “Sister” Archer-Gilligan was a Windsor, Connecticut, nursing home proprietor and serial killer. She killed at least 5 people by poisoning them. One of her victims was her second husband, Michael Gilligan, while the others were the residents of her nursing home. Take a look below for 22 more fascinating and terrifying facts about Amy Archer-Gilligan.

1. It’s possible that she killed more people as the authorities found about 48 deaths in her nursing home, the Archer Home for the Elderly and Infirm.

2. She was born in October, 1873, to James Duggan and Mary Kennedy in Milton, Connecticut. She was the eighth of ten children.

3. She married James Archer in 1897 and had a daughter, Mary J. Archer. They first became caretakers in 1901, when they were hired to care for John Seymour, an old widowers.

4. When Seymour died, his heirs converted the residence into a boarding house for the elderly and the Archers stayed to run a nursing home, paying rent to Seymour’s family.

5. Once Seymour’s family decided to sell the house, the Archer’s moved to Windsor, Connecticut and used their savings to buy their own residence on Prospect Street in Windsor Center.

6. James Archer died in 1910 due to Bright’s disease, which a generic term for kidney disease. Amy took out an insurance policy a few weeks before he died, which enabled her to operate the Archer Home.

7. In 1913, she married Michael W. Gilligan, who was a widower with 4 adult sons. He was wealthy and invested heavily in the Archer Home. After 3 months of marriage, he died and the official cause of death was ruled as acute bilious attack, or severe indigestion.

8. Before he died, Amy forged his will and left his entire estate to her.

9. Between 1907 and 1917, there were 60 deaths in the Archer Home. Because of this, relatives of her clients grew suspicious.

10. Among the deaths was Franklin R. Andrews, who was an apparently healthy man. On May 29, 1914, he was doing some gardening in the Archer House, but by the evening he collapsed and died. The official cause of death was a gastric ulcer.

11. When Andrews’ siblings went over some of his letters they noticed that Amy would press Andrews often for money. Then they noticed that Amy’s clients would often die not long after giving her a large sum of money.

12. As the deaths at the Archer House continued, Nellie Pierce, Andrews’ sibling, reported her suspicions to the local district attorney, who ignored her.

13. She later took her story to the Hartford Courant who published several articles on the “Murder Factory.” At this time, the police opened an investigation.

14. Once the bodies of Gilligan, Andrews and 3 other boarders were exhumed and investigated further, it was found that all 5 had died of poisoning, either arsenic or strychnine.

15. Local store owners testified that Amy had been purchasing large quantities of arsenic, supposedly to kill rats.

16. According to M. William Phelps, the author of The Devil’s Rooming House, investigation appeared to show that Amy was buying the arsenic to kill a large number of rats. However, it appeared that she didn’t buy all the arsenic which killed her patients.

17. Further investigation found that Amy was sending her patients to the drugstore to buy large quantities of arsenic, which she would then use to kill them.

18. She was arrested and tried for murder. She was originally tried on five counts but her lawyer had the charges reduced to a single count, which is the murder of Franklin R. Andrews.

19. On June 18, 1917, a jury found her guilty and she was sentenced to death.

20. She appealed and was granted a new trial in 1919. At this trial, she pleaded insanity.

21. Mary Archer testified that her mother was addicted to morphine; however, Amy was still found guilty of murder but was sentenced to life imprisonment.

22. In 1924, Amy was declared to be temporarily insane and was transferred to the Connecticut Hospital for the Insane in Middletown, where she died on April 23, 1962.