Joel's brother Woolf Joel was murdered in Johannesburg in 1898, probably by a blackmailing con-man named Karl Frederic Moritz Kurtze going under the pseudonym of Ludwig von Veltheim. Although there was plenty of evidence that Veltheim had been threatening Woolf Joel, the defense was that Veltheim had not been properly compensated for planning a kidnap scheme against the Boer leader Paul Kruger. That, the all Boer jury, and the mixture of anti-British and anti-Semitic feelings towards the deceased enabled Veltheim to avoid conviction. Freed, he was immediately deported from the Boer territories. For the next decade, Veltheim was following a series of con-games in Europe, but in 1907, he turned up in London, and started making threatening demands against Joel, who reported him to Scotland Yard, and the police arrested Veltheim. There was a trial for extortion, and Veltheim used the same defense he had previously used in Johannesburg, but the British jury was unconvinced and found him guilty. He was sentenced to twenty years' imprisonment.