Who was Mary Ann Cotton and how many people did she kill?

MUM-of-thirteen Mary Ann Cotton killed off husbands, lovers and children in her 21-year reign of terror.

She became one of Britain's worst serial killers, but who was she?

Who was Mary Ann Cotton?

Mary Ann Cotton was born in Sunderland on October 31, 1832.

She was a Victorian wife and mother of 13 children who worked as a Sunday-school teacher and a nurse.

Due to her attractive good looks and innocent charm, Mary managed to pull the wool over everyone's eyes for years.

However, she is seen as one of the worst female serial killers in modern British history, while at the same time being a bigamist, fraudster and a thief.

How many people did she murder?

Cottom is believed to have murdered as many as 21 people.

She used arsenic used to clean homes and get rid of bedbugs, which was readily available from the local chemist.

She would slip her poison into her victim's food and drink allowing it to slowly deteriorate the person's health - making it look they like died from a "natural" disease.

Her killing spree spread across the north east of England as she married countless lovers and had their children before fleeing.

Before she died it's understood she had killed three of her husbands, a lover, eight of her children, seven stepchildren, her mother and a friend.

How did she get away with it?

Mary's heinous crimes went unnoticed for 21 years after murdering her first husband aged 20 in 1852.

She went on to murder eight of her children and seven stepchildren, putting it down to Scarlett Fever.

Infant mortality at the time was almost at 50 per cent and the average life expectancy for men in the 1870s was 41 years old

What was Mary Ann Cotton's fate?

After becoming overly cocky, Mary's killing rate quickened and people became suspicious as to why death followed her around as frequently as it did.

She was soon charged with the death of her stepson Charles but refused to admit to killing him.

She claimed that he had breathed in the arsenic through fumes from green paint on her wallpaper at home.

She became a media sensation as newspaper reporters wrote about her horrific crimes.

During her trial, it's believed court artists were told to change her appearance to make her ugly because she needed to "look the part".

She was hanged at Durham jail on March 24, 1873, aged 40 years old.