Martin was born in 1907 and lived in Montgomery, Alabama, where she worked as a waitress. Between 1937 and 1951 she poisoned six members of her own family with arsenic: her mother, Mary Frances Gibbon; two of her husbands, George Garrett and Claude Martin; and three of her daughters, Emogene, Ann Carolyn and Judith. Each death was recorded as a natural illness at the time, the symptoms of chronic arsenic poisoning resembling gastric disease.
After Claude Martin's death she married his son by an earlier marriage, Ronald Martin. Her own former stepson. In 1951 he was paralysed by what proved to be arsenic poisoning and survived. That is what exposed the case: the investigation of his illness led to the exhumation of the earlier dead, and arsenic was found in all of them.
She confessed and gave insurance money as part of her motive. She was tried for the murder of Claude Martin, convicted, and executed in the electric chair at Kilby prison on October 11, 1957. The last woman executed in Alabama.
She left a written statement asking that her body be examined to find out why she had done it. It is quoted in most accounts of the case and the request was, in a sense, honoured: her brain was examined after death and nothing was found.
A range of 1937 to 1951 is sometimes read as her birth and death years; those are the years of the killings. She was born in 1907 and died in 1957.