Britain's Serial Killer Victorian "Angel Maker" Amelia Dyer Murdered 400 Babies. Creative Commons

An Englishwoman dubbed the “Angel Maker” has emerged as Britain’s worst-ever serial killer after it was revealed that she killed 400 babies in the Victorian era, according to criminal records from 1770 through 1934 placed online by the National Archives.

Amelia Elizabeth Dyer, born in 1829 in Bristol, killed about 400 babies -- mostly illegitimate infants -- between 1880 and 1896. The killings horrified society, and the public outcry led to stronger regulations on adoption and foster care in England.

The Dyer documents are among more than 2.5 million criminal records placed online by a family archive website last week.

The life and horrific crimes of Dyer stand apart among the records that chronicle all manner of intriguing and horrible tales of crime.

A trained nurse, Dyer decided to be a “baby farmer,” a caretaker who would look after children until they were placed in foster care or were adopted, since it was a more lucrative business. She advertised her services and got responses from desperate unwed mothers who gave their children to Dyer for a fee to place them for adoption. Dyer pocketed the fee from the mothers -- mostly impoverished laborers -- but never took care of the babies. Instead, she gave them an opiate drug to keep them sedated and let them starve to death.

Dyer continued her activities for a decade until she was arrested for child neglect and sentenced to six months in prison. It was then that she was believed to have realized that killing the children immediately would be easier and safer than putting them to a slow death.

After her probation period, Dyer moved to Reading, which had liberal adoption rules, and started an adoption agency.

She preyed on unmarried mothers who were more than relieved to hand over their unlucky children to Dyer. Some of the mothers asked her to kill their illegitimate children while others trusted her to find their children a loving home.

Dyer killed the babies by strangling them with a dressmaking tape and threw the bodies to the River Thames. She could continue her crimes unabated as doctors at the time couldn’t differentiate a stillborn baby from one that was strangled, the Daily Mail reported.

She continued her ghastly crimes for about three decades until 1896, when she was arrested after scores of bodies fished out of the Thames aroused suspicion and triggered an investigation. The police ultimately found Dyer after an address in the parcel paper used to wrap the body of a little girl fished out of the Thames was traced to her.

When interrogated, Dyer confessed to the crimes and reportedly told the police: 'You'll know all mine by the tape around their necks,” the Daily Mail reported.

It reportedly took just six minutes for the jury to pronounce her guilty in a trial held at Old Bailey, London. She was sentenced to death and hanged at Newgate Prison June 10, 1896.

The collection of criminal records, which gives insight into crime and punishment in 18th and 19th century England, has been published by family history website and the National Archives.