Amy Archer-Gilligan was born in October 1873 to James Duggan and Mary Kennedy in Milton, Connecticut, the eighth of ten children. She was taught at the Milton School and went to the New Britain Normal School in 1890. Amy married James Archer in 1897. A daughter, Mary J. Archer, was born in December 1897. The Archers got their first job as caretakers in 1901. They were hired to take care of an elderly widower, John Seymour, and they moved into his home at Newington, Connecticut. Seymour died in 1904. His heirs turned the residence into a boarding house for the elderly, and the Archers were allowed to stay. They provided care for the elderly for a fee and in turn paid rent to Seymour’s family. They ran the boarding house under the name “Sister Amy’s Nursing Home for the Elderly.” In 1907, Seymour’s heirs decided to sell the house. The Archers moved to Windsor, Connecticut, and used their savings to purchase their own residence on Prospect Street in Windsor Center. They soon converted it into a business, the “Archer Home for the Elderly and Infirm.” James Archer died in 1910, apparently of natural causes. The official cause of his death was Bright’s disease, a generic term for kidney diseases. Amy had taken out an insurance policy on him a few weeks before his death, so she was able to continue running the Archer Home.

In 1913, Amy Archer-Gilligan married her second husband, Michael W. Gilligan, a widower with four adult sons. He was reportedly wealthy and interested in both Amy and in investing in the Archer Home. Michael Gilligan died on February 20, 1914. The official cause of death was “acute bilious attack,” in other words “severe indigestion.” Amy was once again financially secure because during their short marriage her new husband had drawn up a will which left his entire estate to her. This will was actually a forgery written by Amy. Between 1907 and 1917, there were 60 deaths in the Archer Home. Relatives of her clients grew suspicious as they tallied the large number of deaths. Only 12 residents died between 1907 and 1910, but 48 residents died between 1911 and 1916. Among them was Franklin R. Andrews, an apparently healthy man. On the morning of May 29, 1914, Andrews was doing some gardening in the Archer house. His health collapsed within a day and he was dead by evening. The official cause of death was gastric ulcer. As the deaths continued, Pierce reported her suspicions to the local district attorney. He mostly ignored her. She took her story to The Hartford Courant, a newspaper. On May 9, 1916, the first of several articles on the “Murder Factory” was published. A few months later, the police started to seriously investigate the case. The investigation took almost a year to complete.

The bodies of Gilligan, Andrews, and three other boarders were exhumed. All five had died of poisoning, either arsenic or strychnine. Local merchants were able to testify that Amy had been purchasing large quantities of arsenic, supposedly to “kill rats”. A look into Gilligan’s will established that it was actually a forgery written by Amy. According to M. William Phelps, author of the “true crime” book, The Devil’s Rooming House, investigation appeared to show that Amy was buying the arsenic to kill large numbers of rats. However, it appears that she did not buy all of the arsenic which killed her patients; the doctor and some of the patients had signed off to purchase it. The investigation pursued Dr. King because more evidence was piling up against him. But suspicions were focused back on Amy when someone suggested to clearly check all records of arsenic purchases. When evidence was found of Amy sending her patients to the drugstore to buy quantities of arsenic, the police were able to arrest and convict her.

Amy Archer-Gilligan was arrested and tried for murder, originally on five counts. Ultimately her lawyer managed to get the charges reduced to a single count (the murder of Franklin R. Andrews). On June 18, 1917, a jury found her guilty, and she was sentenced to death. Amy appealed and was granted a new trial in 1919. At this trial, she pleaded insanity. Mary Archer testified that her mother was addicted to morphine. She was again found guilty of murder and was sentenced to life imprisonment.In 1924, Amy Archer-Gilligan was declared to be temporarily insane and was transferred to the Connecticut Hospital for the Insane in Middletown, where she remained until her death on April 23, 1962.