She resided in Flamborough, a coastal village in Yorkshire, England, with her husband, John Broadingham, who was involved in smuggling activities. During John's imprisonment for smuggling offenses, Elizabeth began an adulterous relationship with Thomas Aikney. Upon John's release, Elizabeth and Thomas lived together openly for over three months. During this period, Elizabeth repeatedly proposed the idea of murdering her husband to Thomas, especially when he was under the influence of alcohol.​

On the night of 13 February 1776, Elizabeth feigned reconciliation with her husband and returned to their marital home. She left the door unlocked to facilitate Thomas Aikney's entry. At approximately 11 p.m., Elizabeth woke John, claiming there was an intruder. As John investigated, Thomas attacked him, inflicting fatal stab wounds, including one so severe that the knife remained embedded in John's abdomen. 

John succumbed to his injuries the following day. Elizabeth and Thomas were apprehended, tried, and found guilty of murder. Elizabeth was convicted of "petty treason" for murdering her social superior, her husband. Consequently, she was executed on 20 March 1776 at York's Tyburn on the Knavesmire, first strangled and then burned at the stake. Thomas Aikney was also executed, and his body was sent to Leeds for dissection.​