It was hardly the kind of attack that one has come to expect from al-Qaida. Black-hooded attackers wielding automatic weapons and grenades swarmed into the financial district of Mumbai on Wednesday evening, occupying luxury hotels and taking dozens of hostages. Over 100 people have been killed in the attacks and over 250 wounded. On Thursday, the city-wide standoff with the terrorists continued; the attackers were demanding the release of "mujahedeen" from Indian jails.

Still, the question as to who is behind the brutal assaults remains open. A previously unknown group calling itself the Deccan Mujahideen sent e-mails to news outlets claiming responsibility. Indian Prime Minister Manmohan Singh said in an address to his nation on Thursday that the attacks probably had "external linkages."

Given the highly coordinated nature of the attack, it would be difficult to exclude such a possibility, despite the targets having been "soft targets" like hotels and train stations instead of well-guarded government facilities. There have, however, been no other claims of responsibility -- and certainly none from al-Qaida. Even if Osama bin Laden's followers were somehow involved, the group tends not to make claims of responsibility until well after the fact, often in the form of slickly produced propaganda videos or farewell messages from suicide attackers.

Such was the pattern following the attack on the Danish Embassy in Pakistan last June. For weeks after the car bomb, al-Qaida remained silent. Finally, on the anniversary of the Sept. 11 attacks, the group claimed responsibility.

In India, though, the pattern -- as seen in a number of brutal attacks in recent years -- has been a different one. Indian Islamist groups have often laid claim to the attacks -- and in those cases when they didn't, Indian authorities pinned the blame on them. Indeed, there are almost a half-dozen terror groups on the Subcontinent which could conceivably be behind the attacks on Wednesday and Thursday. And a number of them have contacts to al-Qaida.

Wednesday's attack does follow a pattern that has come to be associated with many terrorist groups in India. Specifically, they tend to conduct a number of simultaneous attacks coordinated across the city, though the individual assaults may make use of various methods. On Wednesday, a whole host of different methods were on display, including hostage taking, spraying innocent bystanders with gunfire and the use of explosives.

Indeed, such tactics have led a number of experts on Thursday to doubt direct al-Qaida participation. "There is absolutely nothing al-Qaida-like about it," Christine Fair, a South Asia expert with the RAND Corporation, told the International Herald Tribune. "Did you see any suicide bombers? … They don't do hostage taking and they don't do grenades," she continued, referring to al-Qaida.

Still, whoever is behind the attacks, al-Qaida is probably pleased by their work. Osama bin Laden's network has an interest in the destabilization of the entire region. Pakistan is certainly number one on that list, but each additional Islamist attack carried out in India has the potential of chipping away at India's ties with Pakistan. And the greater the instability in the region, the easier it becomes for al-Qaida to operate.

Al-Qaida has for years had close ties with terror groups across South Asia, and not just in India. The Taliban from Pakistan or extremist groups from Kashmir or Bangladesh could all have had a hand in the Mumbai attacks. Each of those groups is pursuing independent goals in the region, many of which are complementary to al-Qaida's aims. Cooperation among them is common -- many terror experts have said these groups participate in a sort of outsourcing model of terror attacks.