Amy Duggan "Sister" Archer-Gilligan (October 31, 1873[1] – April 23, 1962)[2] was a nursing home proprietor and serial killer from Windsor, Connecticut.

The case attracted wide publicity at the time and has been cited as an inspiration for the play Arsenic and Old Lace.

[1] They ran the boarding house as Sister Amy's Nursing Home for the Elderly.

[1] 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.

After Andrews' siblings (including Nellie Pierce) came into possession of some of his letters, they noted occasions where Amy Archer-Gilligan was pressing their brother for money.

[1] Amy's clients showed a pattern of dying not long after giving her a large sum of money.

As the deaths continued, Nellie Pierce reported her suspicions to the local district attorney, but he mostly ignored her.

Local merchants were able to testify that Amy had been purchasing large quantities of arsenic, supposedly to "kill rats".

[1] According to M. William Phelps, author of The Devil's Rooming House, investigation appeared to show that Amy was buying the arsenic to kill large numbers of rats.

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.

Ultimately her lawyer managed to have the charges reduced to a single count, the murder of Franklin R. Andrews.