The triple bomb blasts which shook Mumbai on Wednesday, killing nearly 20 people, inevitably recall the terrorist attack of 2008 in which suicide commandos brought death and mayhem to the city's top hotels, railway station and other places for 60 hours.
That attack, in which 160 were killed, lives in the memory because it lasted so long, the targets were elite - such as the Taj Hotel - and so much of the action was caught on surveillance cameras. It was designed to be unforgettable.
The terrible events of 2008 seem even more fresh because the man who scouted out the landing points and the hotels, the Pakistani-American David Headley (born Daoud Gilani) was giving testimony in a US court as recently as May. He described in detail his contacts with Pakistan's Inter-Services Intelligence (ISI) and with the militant group Lashkar-i-Taiba.
Headley, who has been offered a plea bargain to escape the death penalty, has worked variously as drug dealer, informer for the US Drug Enforcement Agency and allegedly as a deep cover agent for the ISI. He may not be the most reliable witness but there can be little doubt about the close links between ISI and Lashkar-i-Taiba.
All of this means that the world is primed for the finger of blame to be pointed at Pakistan again for Wednesday's rush hour bombings. The Indian Home Minister, P Chidambaram, has been careful to say that no evidence points to any particular organisation, but that all groups "hostile to India" are on the radar. The minister has kept the pot of speculation boiling by saying India lives in a troubled neighbourhood and "Pakistan-Afghanistan is the epicentre of terror".
L K Advani, a senior figure in the opposition Bharatiya Janata Party (BJP), has been even more explicit: "Pakistan must dismantle the infrastructure of terrorism that it has created, and the world is aware of that."
With no clues to the identity of the perpetrators, the minister has been on the defensive, insisting that there was no intelligence failure. "The terrorists worked in a very, very clandestine way," he said by way of excuse. This line of argument is unlikely to provide much reassurance to the residents of Mumbai.
This is the fourth major terrorist outrage in India's financial capital since 1993, and still precautions such as surveillance cameras are slow to be introduced. Apart from a visible police presence at railway stations, and a fast-reaction force ready to move into action, little has changed.
Police and intelligence sources suggested that the Indian Mujahideen, an ill-defined group, could be responsible. Little is known about the precise nature of this group's connections with Lashkar-i-Taiba, or rogue offshoots of that organisation. It usually claims responsibility for its attacks, but no such claim has been forthcoming.
What is clear is that it would be insanity for any agency of the Pakistani state to endorse, however remotely, another attack on Mumbai at this time. Pakistan is facing a host of crises: the city of Karachi is torn apart by communal fighting which has killed 100 in a week; the Pakistani Taliban are a growing threat along the Afghan border areas; relations with the US are close to breakdown.
The one stabilising factor is the prospect later this month for a meeting between the Indian and Pakistani foreign ministers, a tentative resumption of the peace process broken off after the 2008 attack.
The merest suspicion of a Pakistani connection with Wednesday's outrage would lead India to cancel this meeting. There are many forces, in both India and Pakistan, who would like to stop it from going ahead, but it is hard to see how that would be in the interest of Pakistan's government or armed forces.
Even more seriously, it would raise the pressure from the US and India on Pakistan to bring to justice the leaders of Lashkar-i-Taiba, originally nurtured by the ISI to fight in Kashmir. The Pakistani security forces are understood to take the view - a self-serving one - that cracking down on LeT would open up another front in the civil conflicts tearing the country apart.
It is also clear that the bombs on Wednesday were not a terrorist spectacular requiring great skill or logistic competence. They were left in vehicles parked in crowded areas with poor security. The targets were ordinary people going home after work. In no sense was it a rerun of 2008. Anyone with sufficient bomb-making knowledge and the explosives could carry out the task.
Without clear evidence no one can be sure of the culpability. But until we have that, it would be useful to focus on some of the history of Mumbai which is often forgotten amid the anger and outrage when bombs go off.
The most famous chronicler of Mumbai is Suketu Mehta, whose novel Maximum City portrays it as a dystopian model for India's future where everyone is on the make. One reviewer called it "an autopsy of a city that is morally dead".
Some commentators see Mumbai's current problems dating from 1992, when a Hindu mob partially destroyed the Babri Masjid at Ayodhya, a sacred site long disputed between Muslims and Hindus. Some 200 Muslims were killed in Mumbai in subsequent unrest.
Luckily India has largely overcome the vicious sectarian passions of the 1990s. But the effect on Mumbai has remained. It is this that Indian security officials refer to when they talk of "local complicity" in the bombings.
The first blasts in 1993 were revenge for the killings, apparently organised by a Muslim crime boss, perhaps with Pakistani support. The bombings of suburban trains in 2006 are thought to have been the work of the Indian Mujahideen.
Against this background it is important that the Indian security services should be publicly reticent about casting blame on Pakistan. In such a complex city as Mumbai, the possibilities are many, including culprits closer to home. The last thing that the region needs is for the bombing to become politicised - and then inevitably internationalised - until the facts are clear.