 Ramnarayan Rawat, a professor of History and specialising in social exclusion in Indian subcontinent, states that the criminal-by-birth castes under this Act included initially Ahirs, Gurjars and Jats, but its enforcement expanded by the late 19th century to include most Shudras and untouchables, such as Chamars, as well as Sannyasis and hill tribes.Castes suspected of rebelling against colonial laws and seeking self-rule for India, such as the previously ruling families Kallars and the Maravars in south India and non-loyal castes in north India such as Ahirs, Gurjars and Jats, were called "predatory and barbarian" and added to the criminal castes list.Some caste groups were targeted using the Criminal Tribes Act even when there were no reports of any violence or criminal activity, but where their forefathers were known to have rebelled against Mughal or British authorities, or these castes were demanding labour rights and disrupting colonial tax collecting authorities.