She was born Sarah Reynolds at Potton in Bedfordshire in about 1819, the daughter of the town barber, Philip Reynolds, and his wife Ann. Her father was imprisoned for debt in 1825 and died not long after his release. Local accounts describe a mother who had a succession of relationships afterwards, and a daughter who grew up tall and good-looking and was seldom without an admirer.
At nineteen she married a local man, Simeon Mead. They lived at Potton for two years and moved in 1840 to Tadlow, just over the county boundary in Cambridgeshire, reportedly to put an end to one of her attachments. A son was born there in February 1840 and christened Jonah. He died at seven months. In October 1840 Simeon died suddenly as well. She was called the Potton Poisoner, after the town.
In February 1841 she married William Dazley and they moved to Wrestlingworth. She invited Ann Mead, a young relative of her first husband, to live with them. William objected, and the marriage went badly from early on; he drank heavily at the village public house and at least once struck her. She told a male friend, William Waldock, that she would kill any man who hit her.
William then fell ill. Dr Sandell of Potton prescribed pills and he began to recover, and Sarah went on fetching more of them. She was seen throwing the prescribed pills away and putting something else in their place; challenged, she said she did not trust the doctor and had been to the village healer instead. Ann Mead walked in on her rolling pills of her own, took one of them herself to persuade William they were safe, and both of them were violently ill. Both survived that. William Dazley died on October 30, 1842.
The bodies of Simeon and Jonah were exhumed. Arsenic was found in the child. Simeon's body was too far decomposed to give any result, which is the reason that death has never been more than a suspicion.
She was arrested in March 1843 by an officer named Blunden, and told him she knew nothing whatever about poisons and had never obtained any. The journey back to Bedford needed an overnight stop at the Swan Inn at Biggleswade, where she was put to sleep in a room with three of the women who worked there and spent the night asking them about capital trials and about hanging. They told Blunden, who thought it strange.
Committed to Bedford Gaol on March 24, she spent the wait producing defences. In one, William had poisoned himself by accident. In another, William had poisoned Simeon and Jonah in order to have her to himself, and she had poisoned him in revenge. Neither was believed, and the second made little sense at a trial for William's murder.
She was tried on July 22, 1843 at the Bedfordshire Summer Assizes before Baron Alderson, on the charge the prosecution thought strongest. The chemists who had sold her arsenic gave evidence. So did Ann Mead, and a neighbour named Mrs Carver, both of whom had seen the pill-making, and William Waldock, who repeated what she had said about killing a man who hit her. The arsenic in William Dazley's body was demonstrated by the Marsh test, a method then only a few years old, and it was put before the jury as forensic evidence. The jury took about half an hour. Alderson, sentencing her to death, called her utterly heartless.
She was hanged outside Bedford Gaol at Gallows Corner on Bromham Road on August 5, 1843. Reports put the crowd at over ten thousand.
Three points on the record. She is often described as the last woman to be publicly hanged in England; the more careful accounts say the last in Bedfordshire, or the only woman publicly hanged at Bedford Gaol, and this entry follows those. Her year of birth is given as 1819 in most accounts and as 1815 in one. And Ann Mead is described as Simeon Mead's daughter in some accounts and as his sister in others.
On the archive's own classification: she was convicted of one murder and is flagged accordingly. Local writing on the case notes that she is sometimes claimed as the first female serial killer in the United Kingdom, and that the claim fails on the same point, since only one of the three deaths was ever proved against her.