He said the bomb, which was timed to go off around 8:00 am on Tuesday was detected by a hotel worker at around 5:00 am. Had it exploded it would have caused heavy losses in the city,s most congested area, Khan told AFP by telephone.It was recovered almost two hours after a small home-made device exploded outside a Christian missionary school, about half a kilometre away, he said. The pre-dawn blast caused no damage to the school building and no casualties. The police officer ruled out involvement of any terrorist group in the blast blaming it on a local criminal gang. He said efforts were underway to arrest the group and said there had been several attacks in the past.