On Easter Sunday for Western Christian denominations (April 21), three churches in Sri Lanka were attacked by terrorists. While three luxury hotels and a guest house were also hit in apparently coordinated attacks, it appeared that the Christians were targeted in particular. Authorities have reported that about 250 people were killed in the attacks and 500 more injured. Smaller incidents were also reported during the following week as security forces hunted for those linked to the Easter attacks. The horrific massacres point to a serious failure by Sri Lankan authorities and the international community to fight terrorism. Reminiscent of earlier similar attacks against houses of worship in Sri Lanka, the bombings expose the underlying religious and ethnic tensions that have marred the country in recent decades. It is too early in the investigation to determine all those responsible and their motives, but Sri Lankan authorities have pointed to members of the National Thowheeth Jama’ath, a little-known local group, as the main culprits. There are reports that they have links with extremist groups based in India and elsewhere. Although Daesh has claimed responsibility, it is not yet clear in what way it is linked with the local group. If such links exist, it means that the Global Coalition against Daesh has failed to adequately address the dangers of the group’s fighters dispersing worldwide following the loss of its territories in Syria and Iraq. In Sri Lanka’s diverse society, the Buddhist Sinhalese constitute about 70 percent of the total population of 23 million, Hindus 12 percent, Muslims 10 percent, and Christians 7 percent. Although Sri Lanka’s constitution provides for freedom of thought, conscience and religion, the law gives Buddhism the “foremost place” among the country’s religious faiths and commits the government to protecting it while respecting the rights of religious minorities. Relations between Sri Lanka’s religious and ethnic communities have not always been peaceful, especially between the majority Buddhist Sinhalese and the Hindu Tamil community, some of whose members have sought separation from Sri Lanka. Innocent civilians were frequently targeted during the civil war that lasted from 1983 to 2009. For decades, it was the Liberation Tigers of Tamil Eelam (LTTE) separatist group that was associated with large-scale terrorist attacks. They were notorious for assaulting Muslim and Buddhist houses of worship, exploding aeroplanes in mid-air, hijacking buses and trains, assassinating politicians, and wiping out large numbers of peaceful civilians. For example, in 1985, the LTTE attacked a Buddhist shrine in Anuradhapura and gunned down nuns, monks and innocent worshippers. In 1987, the group pulled out 127 Buddhist Sinhalese men, women and children from three buses and executed them. Later that year, they bombed the central bus station in Colombo, killing 113 civilians, and attacked a Buddhist shrine, killing and mutilating 33 Buddhist monks.In 1990, LTTE terrorists killed more than 147 Muslim men and boys in a mosque in Kattankudy. In 1991, they attacked a Muslim village and killed 182 civilians (171 of them Muslims). In 1995, they massacred 42 men, women and children in one attack — the victims were mainly Sinhalese Buddhists. In 1996, the LTTE bombed Sri Lanka’s Central Bank, killing 90 people and injuring 1,400 more, and also bombed a commuter train, killing 64 civilians and injuring 400. In 2009, an LTTE suicide bomber attacked a Muslim gathering, killing 14 and injuring 35 civilians. The list goes on, giving the LTTE a notorious reputation comparable to that of Daesh today. In the final weeks of the insurgency in 2009, it is estimated that 40,000 mostly Tamil civilians were killed in the government"s brutal final attacks. Many LTTE fighters, including their leader, were summarily executed. In the subsequent feverish upsurge of Buddhist Sinhalese nationalism, Muslim and Christian civilians were attacked. Before the Easter attacks, the Muslim and Christian communities, as the weakest minority groups in the country, refrained from attacking each other and lived in relative harmony. Largely peaceful, Sri Lanka’s Christians have suffered increasing persecution. According to the 2017 International Religious Freedom Report issued by the US Department of State, Christian churches “continued to report physical attacks and harassment by police and local government officials.” The report noted an increase in those attacks from 89 in 2016 to 97. The report also relates that local officials and police “responded minimally or not at all to numerous incidents of religiously motivated violence against Muslim and Christian minorities.” The investigations into the Easter Sunday attacks could benefit from international cooperation and expertise to identify those directly or indirectly responsible for the attacks. Given the troubled history of community relations in Sri Lanka and the growth of violent Buddhist Sinhalese nationalist groups, international involvement would give more credibility to the investigation. And, because of the likely international links between local terrorists and outside groups, international cooperation is going to be necessary. In addition to bilateral assistance in the investigation from relevant countries, the Global Coalition against Daesh also has access to considerable information that could help in the investigation. It also has a duty to assist in uncovering any Daesh links to the Sri Lanka attacks.