Dorethea van der Merwe, also known as Dorethea Kraft, was a widow residing on the Treurfontein farm in the Lichtenburg district of Transvaal, South Africa. She lived there with her daughter, Polly. The farm faced challenges due to drought and poor soil, making it difficult to sustain. Additionally, Dorethea encountered resistance from her laborers, who were reluctant to take orders from a woman.

In 1914, Louis Tumpowski, a Polish Jew and peddler, visited Treurfontein seeking fresh produce for his business. At that time, Dorethea was divorced and struggling with her farm operations. Tumpowski offered to manage the farm, and they entered into a lease agreement where he would pay annual rent with the option to purchase the property eventually. Over time, Dorethea and Tumpowski lived together as man and wife.

By 1918, tensions arose when Tumpowski expressed his intention to exercise his option to buy Treurfontein at a price below its market value. Feeling deceived and desperate to retain ownership, Dorethea sought assistance from a local witch-doctor, Jim Burds, to influence Tumpowski into marrying her, hoping to secure her claim to the farm. When these efforts failed, she enlisted the help of Hermanus Lambertus Swartz, a distant relative and army deserter.

On the stormy night of February 2, 1918, Burds arrived at Treurfontein at Dorethea's request. He struck Tumpowski on the head with a heavy stick, and Swartz followed by tying a leather thong around Tumpowski's neck and slitting his throat. They buried his body in an ash pit on the farm. Tumpowski's sudden disappearance did not initially raise suspicion. Subsequently, Dorethea moved to another district, remarried, and became known as Mrs. van der Merwe.

However, Tumpowski's sister in Johannesburg grew concerned when her letters were returned unanswered. She reported her suspicions to the police, prompting an investigation. Despite initial searches yielding no results, a violent windstorm two years later caused a subsidence in the ash pit, revealing Tumpowski's remains. Dorethea van der Merwe and Hermanus Swartz were arrested and stood trial in Potchefstroom on June 13, 1921. Both were found guilty and sentenced to death.

In August 1921, Dorethea was executed by hanging at Pretoria Central Prison, becoming the first woman to be hanged under the Union of South Africa.