Turpin most likely became involved with the Essex gang of deer thieves in the early 1730s. Deer poaching had long been endemic in the Royal Forest of Waltham, and in 1723 the Black Act (so called because it outlawed the blackening or disguising of faces while in the forests) was enacted to deal with such problems. Deer stealing was a domestic offence that was judged not in civil courts, but before justices of the peace; it was not until 1737 that the more severe penalty of seven years' transportation was introduced. However, in 1731 seven verderers became so concerned by the increase in activity that they signed an affidavit which demonstrated their worries. The statement was lodged with the Duke of Newcastle, Secretary of State, who responded by offering a £10 reward to anyone who helped identify the thieves, plus a pardon for those thieves who gave up their colleagues. Following a series of nasty incidents, including the threatened murder of a keeper and his family, in 1733 the government increased the reward to £50 (about £ as of ).