Margaret Higgins was born in Ireland around 1843. During the mid-19th century, she migrated to Liverpool, England, likely seeking better opportunities amidst the socio-economic challenges of the time. Margaret lived with her sister, Catherine Flannagan, at 5 Skirving Street, where they operated a boarding house. Despite their efforts, the sisters faced financial hardships, leading them to exploit burial societies—organizations that provided financial assistance for funerals upon a member's death.

The sisters' deadly scheme began with the sudden death of Catherine's son, John Flannagan, in December 1880. His passing allowed Catherine to collect £71 from his burial society. In October 1882, Margaret married Thomas Higgins, a lodger at their boarding house. Shortly after their marriage, Thomas's 8-year-old daughter, Mary, died suddenly, and Margaret collected the insurance payout.

In January 1883, another lodger, 16-year-old Margaret Jennings, died under mysterious circumstances, with Catherine receiving the burial society payment. The pattern of sudden deaths and financial gains continued, raising suspicions among the local community.

The turning point came in September 1883 when Thomas Higgins fell ill and died after two days of severe suffering. Initially attributed to dysentery from excessive drinking, his death certificate did not raise immediate alarms. However, Thomas's brother, Patrick Higgins, grew suspicious upon discovering multiple insurance policies taken out on Thomas's life. He demanded a post-mortem examination, which revealed lethal amounts of arsenic in Thomas's system.

Subsequent investigations led to the exhumation of the previously deceased household members, all of whom were found to have died from arsenic poisoning. Authorities uncovered arsenic in the sisters' residence, and both women were arrested and charged with murder.

In February 1884, after a three-day trial, Margaret and Catherine were found guilty of the murder of Thomas Higgins. Despite suspicions of additional murders, they were only tried for this single case. On March 3, 1884, the sisters were executed by hanging at Kirkdale Prison in Liverpool.