Nearly 500 people have been killed in nine well-co-ordinated terrorist attacks across India since the Diwali-eve bombings here in 2005, but no case has been resolved and no terrorists arrested.

Authorities admit the terrorists are getting more sophisticated and appear linked to one another, investigations invariably reach dead ends after the initial enthusiasm to find the guilty.

Nine powerful bombs went off in 15 minutes in crowded areas in the heart of Jaipur last Tuesday, killing 61 people and wounding 216.

They were the latest in a series of carnages that started in New Delhi in October 2005 when more than 60 people were killed just before Diwali.

The worst were the synchronized attacks on Mumbai’s commuter trains in July 2006 that claimed 187 lives.

Twin bomb blasts in Hyderabad in August 2007 left 40 dead.

A bomb also ripped through the Samjhauta Express travellinging to Pakistan from India, killing many Pakistanis.

There also have been blasts in Ludhiana in Punjab, Malegaon in Maharashtra and at the Hazrat Khwaja Moinuddin Chisti shrine at Ajmer in Rajasthan.

Last year, bombs went off in courts in Uttar Pradesh.

The victims have included Muslims and Hindus.

No one knows for sure who is planting the bombs — and who are the masterminds. The suspicion in most cases has fallen on Islamist groups, based in India and abroad, particularly in Bangladesh and Pakistan. But there have been no firm leads.

Now, there is a call for a separate national authority to deal with crimes threatening the country’s security, or perhaps arming the Central Bureau of Investigation (CBI), the top investigative agency, with a federal role, similar to that of the Federation Bureau of Investigation (FBI) in the United States.

"We are already late in creating such an agency. It is beyond the resources and capacity of some state governments to tackle terror. Therefore it becomes more imperative to get such an agency off the ground at the earliest," says Madhava Menon, the head of a government-appointed committee that made the recommendation.

Menon says such a professional body should be autonomous, like the Election Commission. He adds that the CBI is not independent enough for the job nor does it have the resources, jurisdiction or personnel.

Ajay Sahni, who edits the South Asia Intelligence Review and is an authority on subcontinental terrorism, says more needs to be done to augment the police capacities and improve intelligence systems.

"There is no coherence in the national response to terrorism, no evidence of consistent strategy or policy perspective, no institutional memory or visible learning process within the various institutions of governance," Sahni said. "We need to derive lessons of past campaigns."