Pakistani Christians closed missionary schools on Monday in protest after a Muslim mob torched more than 100 Christian homes following allegations of blasphemy. More than 3,000 Muslims rampaged through Joseph Colony, a Christian area of the eastern city of Lahore, on Saturday after allegations that a Christian had made derogatory remarks about the Prophet Mohammed three days earlier. Police said they were investigating whether Muslim businessmen in the area may have instigated the violence either as an effort to seize the Christians\' land or to exploit the blasphemy allegations for political gain.  No-one was killed but the incident triggered protests around Pakistan from Christians, a tiny minority in overwhelmingly Muslim Pakistan, demanding better protection.\"Missionary schools of Lahore will remain closed on Monday on account of massacre in Joseph colony,\" Bishop Sebastian Shaw, chairman of the Catholic board, told reporters. The schools are considered among the best in Pakistan and are extremely popular with wealthy Muslim families, with pupils taught in English in a disciplined and effective learning environment. Church officials said schools were also closed throughout Sindh province, including Karachi, and the southern part of Punjab, where many Christians live in the main city Multan and many others are settled in villages to work in agriculture.  The violence erupted on Saturday morning after a Christian sanitary worker was accused by his Muslim friend of making derogatory remarks about the Prophet Mohammed. Police held 150 people on charges of riot and arson over the incident and on Monday a court sent 21 on judicial remand, while a further 26 are in police custody pending inquiries.Senior police investigator Chaudhry Shafiq Ahmed told AFP officers were looking into claims local traders may have sought to exploit the incident for their own ends. \"We are investigating local traders\' leaders, because the elections of the local traders\' associations were due on March 20 and there are complaints that they also actively participated in the attacks on Christians houses,\" he said.  Pervez Masih, a local Christian resident said that most of the attackers were the workers from nearby factories. Another Christian resident speaking on condition of anonymity said dozens of activists of the hardline Sunni Muslim group Ahle Sunnat Wal Jamaat (ASWJ) came from the local mosque to join the rioters. \"There is a growing transport business in the area and the transporters had been asking the residents to sell their houses, so that they could set up their goods transport business,\" he said.A local Muslim resident said that the Muslim residents of the area were disturbed over selling of bootleg liquor by Christians in the area. Police and locals said a drunken row between the Christian and his Muslim friend lay at the root of Saturday\'s violence, which highlights the religious tensions affecting Pakistan as it prepares for a general election expected in May. Already this year more than 250 people have been killed in a spate of bloody attacks on the minority Shiite Muslim community. Blasphemy is a very sensitive issue in Pakistan and even unproven allegations can spark a violent public response. Rights campaigners argue the country\'s strict blasphemy laws, which include the death penalty, are often abused to settle personal scores and should be reformed.