Punjab's radical preacher Amritpal Singh, who was at the centre of a massive protest against the arrest of his key aide, has blamed the Punjab Police for the violence in Amritsar on Thursday. Often escorted by armed supporters, the radical preacher and Khalistan sympathiser has been active for some time in Punjab. Mr Singh heads "Waris Punjab De", a radical organisation started by actor and activist Deep Sidhu, who died in a road accident in February last year.