Elizabeth Prater was born c. 1842 in London. In 1868 she gave birth to her first child, Charles Elder. Her second child, Kate Elder, was born in 1869. It is unknown if she was married to the childrens' father, or what became of him. In any case, she married William Prater in 1873. By this point she had possibly borne one child by him, a daughter named Elizabeth who was born in 1872, but who may also have been the daughter of William's previous wife. Prater claimed that she and her husband separated c. 1883. Nonetheless that had at least one more child together, a son named Thomas who was born in 1884. This suggests that the pair may have gotten together briefly after the separation, a supposition supported by their later frequent separations and reconciliations.
By 1888 she was earning her living as a prostitute in London's East End. She lived above Mary Jane Kelly, at 20 Miller's Court, itself at 26 Dorset Street, Spitalfields. She reported leaving the court at about 9 p.m. on November 8th, when she encountered Kelly for the last time. The two women briefly spoke, before Prater left to ply her trade, returning to the court at about 1 a.m. the following morning. When she returned she reported waiting in the court for a man she shared the room with to return, and, when he failed to arrive, speaking with John McCarthy, who she claimed was the only person she saw enter the court. After this she went up to her bed. She was awakened between 3:30 and 4:00 by her kitten, Diddles, crawling across her neck. She claimed that at this time she heard a woman faintly scream "murder" two or three times. As this was a commonplace cry heard in the area she ignored it. At 5:30 she awoke again and went to a pub, seeing nothing unusual in the court. she returned to the court and went back to sleep, sleeping until about 11 a.m. Unlike other witnesses living in the court she did not report hearing Kelly singing anything during the night until several years later, when she was interviewed by a journalist.
By 1891 she and her husband had reconciled, and she was living with him. In 1892 she was back at Miller's Court. They were listed together in 1901, but she was again listed as living in Miller's Court in 1902. No other documentation exists of her life.