India has been reticent to point the finger at its western neighbour as investigators probe the deadly triple bombing that struck Mumbai earlier this week. But analysts say it may be difficult to rule out links to Pakistani militants in the terrorist attacks.
Wednesday's bombings killed 17 people and injured 131 others, making them the deadliest on Indian soil since the November 2008 siege of Mumbai, in which 166 people died.
Investigators have descended on the three neighbourhoods where near simultaneous blasts erupted in the country's financial capital Wednesday evening, reviewing video from surveillance cameras and searching for forensic evidence as monsoon rains washed down the city's streets.
No group has claimed responsibility for the attacks, and Indian officials have refused to speculate on who may be behind them.
"All angles will be examined without any predetermination," Home Minister Palaniappan Chidambaram said at a news conference in Mumbai on Thursday. "All groups hostile to India are on the radar."
Terrorist bombings are nothing new in the world's second most populous nation, where a number of radical groups -- including Maoist rebels, Kashmiri separatists and Islamic militants -- are active.
Speculation about who might have carried out the attacks has focused on "homegrown" Islamic militants in India. But that may not mean they were operating without assistance from groups based elsewhere on the subcontinent.
"From my point of view, any Islamist militant actor in India is likely to have some sort of relationship with Pakistan-based entities," said Kamran Bokhari, an analyst with global intelligence firm Stratfor.
Bokhari said Pakistani militants have a particular interest in stoking tensions between India and Pakistan to divert attention from their activities, and to shift Islamabad's focus away from the war in Afghanistan.
"The bottom line is, what will the Indians determine -- is there a Pakistani link or not?" he told CTVNews.ca. "That's the million-dollar question."
Tensions rose between India and Pakistan after the 2008 Mumbai attacks, which Islamabad eventually admitted had been planned partly on its territory.
But speculation about who carried out Wednesday's bombings has focused on the Indian Mujahideen, which has claimed responsibility for a number of attacks in the country since 2007.
Counterterrorism officers in Kolkata have been hunting for a suspected member of that group who disappeared days before the bombing, The Times of India reported early Saturday.
While the investigation goes on, reluctance on the part of Indian officials to level accusations suggests that "the government is especially concerned over jumping to any conclusion which is not evidence-based," said Rahul Roy-Chaudhury, a senior fellow with the International Institute for Strategic Studies who has served on India's National Security Council Secretariat.
Indian authorities need to consider "all options" including Pakistan-based groups, Roy-Chaudhury said by phone from London, England.
"But I tend to think we need to look inwards more," he added.
New Delhi took a number of steps to shore up its counterterrorism apparatus in the wake of the 2008 Mumbai attacks, better equipping and training police, and creating institutions to more quickly respond to and investigate terrorist attacks.
But it hasn't been enough, Roy-Chaudhury said. For instance, "there is no excuse" for India's police, military and intelligence agencies failing to share information.
"What the heck has been going on for the past two-plus years here?" he asked. "I think there needs to be introspection really to see what went wrong."
