The prime suspect behind the deadly Mumbai attacks

Was it al-Qaeda - or a home-grown terrorist? The prime Indian suspect in the spectacular terrorist attacks on Mumbai will be Abdul Subhan Qureshi, a 36-year-old computer engineer who is also believed to have masterminded multiple bombings in Delhi, Jaipur, Bangalore and Ahmedabad earlier this year.

It is too soon to say who is responsible for the co-ordinated strikes by gunmen on India's financial capital - ­ targets included luxury hotels, railway stations and hospitals - but Qureshi, also known as Tauqeer, is the man Indian security services will be fingering.

His profile is typical of the modern Islamic militant - educated, intelligent, the first generation of a family to break through to middle-class status and, as is very often the case, the first to grow up in a city, in this case Mumbai.

Qureshi is not known to be linked with al-Qaeda: his association is with the Indian Mujahideen

Qureshi's parents came from the poor, crowded northern state of Uttar Pradesh but migrated to the city ­ - then called Bombay - and sent their son to Antonio De Souza High School, a church-run institution catering to all major religions.

He went on to get a diploma in industrial electronics in 1995, then a more specialised computing qualification in 1996 before joining a technology firm. From there, after handling several major projects, he moved to a larger computer company and then resigned suddenly, explaining that he wanted to "pursue religious and spiritual matters".

Qureshi is not known to be linked with al-Qaeda: his association is with the Indian Mujahideen, which claimed responsibility for the earlier bombings in other Indian cities and after the Delhi attack issued an explicit threat that Mumbai would be next.

(In emails to the Indian media, a group calling itself the Deccan Mujahideen has claimed responsibility for last night's attacks, but it is not known to anti-terrorist experts and may turn out to be a hoax.)

If Qureshi is responsible, the question is whether he has miscalculated with this latest attack. The tipping point in a terrorist campaign comes when a community becomes sick of the violence. Then you get the stream of intelligence that leads to an individual.

This has happened in Iraq ­ with Abu Musab al-Zarqawi, in Egypt during the 1980s, in France, in Indonesia and in the UK. Tips from within the British Muslim community have led to scores of important arrests in recent years. It is the only way a manhunt can be successful.

Those the bombers claim to represent are least likely to be affected by the attacks

But it's not always that simple. One reason Osama bin Laden is still at large is that the strikes he orchestrates are a long way from the local population that might turn him in. The people who might be sickened enough by the sight of the real effects of his acts find themselves instead under the bombs and missiles of the Pakistani and American militaries.

In India, the situation is complicated too. The people the bombers claim to represent are least likely to be affected by the Islamic militants' attacks, if they are indeed responsible: few among India's 151m Muslims have had the education and economic opportunities to end up in the Taj Mahal Palace Hotel, which, of course, is one of the motivations of the terrorists.

Depriving the terrorists of any legitimacy within the eyes of the traditionally moderate and law-abiding Indian Muslim community will be essential if they are to be stopped.

While Qureshi is without doubt a prime suspect, various aspects of the Mumbai attack point to al-Qaeda, as Robert Fox reports for The First Post: the degree of co-ordination, the timing - Western intelligence has been expecting an atrocity of some sort while Barack Obama waits to take over in Washington - and the reports from eyewitnesses that the gunmen who attacked the Taj and the city's other landmark hotel, the Oberoi, were specifically seeking out guests with American and British passports.

Whoever is responsible for last night's wave of terror has left Mumbai in chaos, with more than 100 killed, including the state's anti-terrorism chief, Hemant Karkare.

Ten were shot dead at the Chhatrapati Shivaji railway station, formerly known as the Victoria terminus. And at both the Taj and the Oberoi, gunmen were still holding Westerners hostage this morning.

Jason Burke is a senior foreign correspondent for the Observer