Punjab Police on Tuesday booked over a dozen people following an assault on a Sikh leader inside a gurdwara complex in Gurdaspur district.The assault on Johar Singh, President of the managing committee of Chhota Ghallughara Gurdwara at Qadian, took place late on Monday night.A number of men and women assaulted Singh. His turban fell down during the attack and most of his clothes were torn, the police said.A video of the attack went viral within hours.Singh belongs to a camp of Sikh leadership who are seen as rivals to the hold of the SGPC (Shiromani Gurdwara Parbandhak Committee) and the Akal Takht, the highest temporal seat of the Sikh religion.The police had to intervene on October 12 at the Golden Temple complex in Amritsar as rival Sikh groups clashed.The incident at the complex, where the holiest of Sikh shrines 'Harmandir Sahib' is located, left several people injured.Singh was summoned by the 'parallel jathedars' to clarify his stand over the ruckus created at the Qadian gurdwara in August following allegations of involvement of a member of the gurdwara management in immoral activities.The 'parallel jathedars' were appointed by hardline Sikh groups in 2015. The SGPC and Akal Takht do not recognise them.