Since 1840 the attention of the government had been drawn from time to time by different local officials to the dangerous and ‘seditious’ character of the activities of the Wahhabi centres in British India. In 1858 and even more so in 1863 the government had to organise full-scale military expeditions against the Wahhabi centre on the Frontier. For about ten years since 1863 extensive police enquiries were carried on and a large number of Wahhabi workers and sympathisers were detained and interrogated at different places all over the country, such as Malda, Rajmahal, Patna, Thaneswar, Ambala and Delhi. The enquiries were followed by a long series of trials spread over a decade. These trials were held at Ambala (1863), Patna (1865), Rajmahal, Malda and again Patna (1870–71). Of these, the Ambala and Patna Trials were the earliest and the most important. They set the pattern for subsequent government proceedings.