Four persons were killed and 24 others injured when the moving bus, mostly ferrying devotees, caught fire near Nomai, about three kilometers from Katra, shortly after leaving for Jammu from the base camp on Friday. Though the survivors and the people residing in the vicinity of the incident spoke about hearing an explosion in the bus, Additional Director General (ADG) of Police, Jammu zone, Mukesh Singh, who inspected the scene, said the initial probe does not point to use of any explosive. "The bus caught fire on its way from Katra to Jammu. The cause of the fire is not confirmed yet," Singh had told reporters, adding a forensic team is looking into it.