Truelock was a shoemaker and a religious fanatic who prophesied the second coming of Jesus Christ. He also insisted in the belief that the Messiah would be born from his mouth. In December 1800, he was admitted to Bethlem Royal Hospital for have allegedly persuading James Hadfield that by shooting George III, Hadfield would bring peace to the world.
- Eigen, Joel Peter. "Hadfield, James". Oxford Dictionary of National Biography (online ed.). Oxford University Press. doi:10.1093/ref:odnb/41013. (Subscription or UK public library membership required.)
- Dickens, Charles. All the Year Round: A Weekly Journal. 17. Missing or empty
- Poole, Steve. The Politics of Regicide in England, 1760-1850: Troublesome Subjects. Manchester University Press. p. 124. ISBN 0719050359.
- Andrews, Jonathan. The History of Bethlem. Psychology Press, 1997. p. 390. ISBN 0415017734.