Even as the siege of Mumbai was still going on, the finger-pointing began. India's Prime Minister Manmohan Singh said "external forces" were behind the attacks, a thinly veiled reference to India's neighbor and longtime foe Pakistan. Foreign Minister Pranab Mukherjee went further, telling reporters that "elements with links to Pakistan" were involved. But Pakistan's President and Prime Minister both condemned the attacks and rejected any talk of Pakistani involvement. Pakistani officials also announced that the head of the powerful Inter-Services Intelligence organization (ISI) often accused of orchestrating terrorist assaults on India would travel to India to offer assistance in investigating the Mumbai massacre.
There has been one claim of responsibility: a group calling itself the Deccan Mujahideen, which e-mailed news organizations on Thursday claiming it had carried out the attacks. The group, previously unknown, may be connected with (or even an alias of) the Indian Mujahedin, which claimed responsibility for several terrorist strikes earlier this year. Indian terrorism experts say that both are likely to have connections to, or simply be renamed versions of, older Indian militant groups such as the Pakistan-based Lashkar-e-Toiba or the Students Islamic Movement of India. (See pictures of two days of terror in Mumbai.)
Yet the scale and sophistication of the Mumbai attacks which appear to have involved dozens of militants using assault rifles, grenades and explosives to simultaneously attack multiple targets raise suspicions of involvement by more than one group, which would involve an unprecedented level of coordination.
"This is an operation of a very new type in India," wrote Walid Phares on his well-respected Counterterrorism Blog. "The 'emirs' have sent these armed elements in their 20s to strike at Indian psyche. One goal is to sink the Pakistani-Indian rapprochement ... The goal is to target India as a power engaged in the war on terror but also to further destabilize the region, including Pakistan and its neighbor Afghanistan."
Here are the groups considered the most likely culprits in the Mumbai attacks:
Despite the ideological affinities of some of these groups with bin Laden's movement, Ajai Sahni, executive director of the New Delhibased Institute for Conflict Management, says there is no real evidence "of any operational linkages between al-Qaeda and these groups." They may take inspiration from al-Qaeda propaganda, but they are unlikely to have direct organizational links back to bin Laden.
More likely, however, is that the four separate groups have begun to work together more often and in increasingly sophisticated ways. There have been instances in the past of the groups' establishing joint operational cells. While pooling resources allowed for more effective operations, it also greatly increased the risks of police infiltration. As a result, the planning of such operations has been decentralized to the point that each group of militants attacking a specific target in Mumbai on Thursday was unlikely to have been aware of the total plan.
Sahni explains that previous experience suggests that an operation of the complexity of the Mumbai attacks would be directed by handlers based outside India, who would design a plan and then contact militants within their networks based in India to carry out various missions delivering explosives to a safe house, buying equipment and so forth that would enable the gunmen to wreak havoc.
None of the India-based operatives would most likely know one another, nor for the most part would even meet. Contact with the handler woould always be through a public call center to make it difficult to trace calls. If an operative were picked up by police, there would be no way for him to identify fellow plotters. "It assures total anonymity," Sahni told TIME last year. "The handler is in Bangladesh or Pakistan, and the people here don't know each other. It's the most significant tactical shift in the near past and is a model for international terrorism in the future."
Sadly, the success of the Mumbai operation at least 143 dead and, perhaps more important, two days and counting of continuous news coverage is sure to embolden those behind it. The Indian model of disparate groups working together, if that's what it is in this case, is also likely to be copied by al-Qaeda-inspired terrorists around the world. The model, says Sahni, "is absolutely brilliant in every way."