For decades, one half of Britain’s most infamous criminal partnership lived behind a mask of domestic normalcy, her true nature concealed beneath the routines of family life. To neighbors, she appeared ordinary. To those who visited the home on Cromwell Street, nothing seemed outwardly amiss.

Yet the truth inside those walls was almost unimaginable.

Together with her husband, this woman participated in a series of murders and sexual assaults that would horrify Britain for generations. Their victims included young women lured into their home — and even their own children. Over more than two decades, the pair carried out acts so brutal and calculated that they remain deeply disturbing even today.

To understand how a seemingly unremarkable young woman became one of history’s most notorious killers, we have to go back to the beginning — long before she ever met the man who would shape her into a partner in violence.

A childhood that looked perfect — from a distance
Born in North Devon in 1953, she grew up in a family that, at first glance, appeared traditional and loving. Her father, Bill Letts, had served honorably in the Navy. Her mother, Daisy, was known in the community for her beauty and quiet, gentle demeanor. With six siblings, the household looked lively and complete.

But beneath that façade, instability had already taken root.

Before her birth, Daisy struggled with severe depression. While pregnant, she underwent electroconvulsive therapy — a treatment that involved powerful electrical currents coursing through her body and the unborn child. Even after the baby arrived, something seemed different. She rocked her head rhythmically for long periods, moved in trance-like motions, and appeared disconnected from those around her.