Among important examples of such characteristics are the use of bicycles to plant Improvised Explosive Devices (IED) in crowded places and mixing projectiles like the ball-bearings of cycles with the explosive.

Bicycles as carriers of IEDs have often been used by different terrorist groups since the jihad against the Soviet troops in Afghanistan in the 1980s. Jihadi as well as non-jihadi groups have been using cycles. Among the non-jihadi organisations which use bicycle bombs is the United Liberation Front of Asom, ULFA.

The greatest advantage of bicycles for terrorists is that they are used by millions of people and unattended bicycles left in crowded places do not attract suspicion. Cycles are also used under certain other circumstances -- when the terrorist organisation has only limited funds, when it has no capability for stealing cars and motorcycles and having them driven to the targeted place and when it wants to use an unconscious cut-out for having the IED reached to the spot without using its cadres for this purpose.

ULFA uses such cut-outs for having cycles fitted with IEDs left in crowded areas for which they are paid. In this manner, ULFA cadres escape identification and arrest.

Ball-bearings are also often used to increase the lethality of the explosive. The LTTE has been using them for nearly 20 years now. When the Sri Lankan authorities imposed severe restrictions on the sale of ball-bearings in the Tamil areas, the LTTE started smuggling them in sackfuls from Tamil Nadu.

By mixing ball-bearings with the explosive, one cannot only increase the lethality of the IED, but one can also economise on the use of the explosive. A small quantity of explosive can cause a large number of casualties if mixed with ball-bearings and other projectiles.

By mixing ball-bearings, a low-intensity explosive can be made to cause a high-intensity killer effect.

The IEDs at Jaipur were activated by mechanical timers. According to published details of one IED, which failed to explode, the timing mechanism was an ordinary clock. This was similar to the modus operandi of the Khalistani terrorists in Punjab in the 1980s.

The new trend among jihadi organisations in other countries has been to use the alarm mechanism of mobile telephones for timing an IED. This was apparently not used in Jaipur.

In recent months, the police in Karnataka, Goa [Images], Uttar Pradesh, Andhra Pradesh and Madhya Pradesh had claimed to have neutralised a number of jihadi sleeper cells constituted by the Lashkar-e-Tayiba, LeT, and the Harkat-ul-Jihad-al-Islami, HUJI, with the help of the Students Islamic Movement of India, SIMI.

During their interrogation, those arrested reportedly spoke of the plans of these organisations to attack Israeli and Western tourists in Goa. In fact, Goa had been repeatedly figuring in interrogation reports as a possible target for attacks by the LeT or the HUJI or both.

Jaipur had not figured in the interrogation reports.

The fact that Jaipur and not Goa was attacked is mysterious. This would indicate one of two things: Either those arrested and interrogated earlier had misled the police by talking freely about Goa when their real target was Jaipur; or the Jaipur blasts were carried out by an organisation totally different from the organisations (the LeT and the HUJI) to which those arrested earlier belonged.

Tourism has been an important target of the terrorists all over the world. Al Gamah Al Islamiyah of Egypt used to attack tourist targets in Egypt in the 1990s. The Jemaah Islamiyah of Indonesia targeted the Australian tourists twice in Bali in 2002 and 2005. Al Qaeda [Images] targeted foreign tourists (mainly Israelis) in Mombasa in 2002, in Casablanca in 2003 and in Sharm-el-Sheikh in Egypt in 2005.

Their primary targets were foreign tourists though locals also got killed. In Jaipur, there was no targeted attack on foreign tourists. No foreigner has been killed. They did not attack restaurants, bars, hotels etc, which are known to be frequented by foreign tourists. The terrorists targeted the tourist potential of Jaipur, not foreign tourists in particular.

Some police officers and embedded journalists have already started blaming the LeT and the HUJI even though the blasts do not carry any unique signature of any organisation. The only way of identifying the organisation responsible is by arresting the perpetrators and interrogating them. Till we reach that stage, it will be premature and unwise to blame anyone.

Almost 24 hours after the blasts, two television channels of New Delhi claimed to have received an anonymous e-mail claiming responsibility for the explosions on behalf of a group called 'the Indian Mujahideen.' The e-mail was purported to have been sent by guru_alhindi_jaipur@yahoo.co.uk

The most significant thing about this message is that it has included the picture of one of the cycles alleged to have been used in Jaipur with the number of the cycle readable. If a cycle with that number had, in fact, been used in Jaipur, this claim could acquire some authenticity.

In the 1980s, the Irish Republican Army used to follow a similar modus operandi whenever it planted an IED. Through phone calls, it used to give clues to the police to enable them to establish the authenticity of the IRA's claim of responsibility.

It may be recalled that before the blasts outside some courts in Uttar Pradesh in November last, a message claiming responsibility for the blasts on behalf of 'Indian Mujahideen' was received by local television channels. There was also a reference to Guru-al-Hindi in another message. This was suspected to be a reference to Afzal Guru, who has been sentenced to death in the case relating to the attack on Parliament in December 2001 and who has appealed for clemency.

The message of November 2007 had also claimed that the Indian Mujahideen had nothing to do with the LeT or the HUJI.

It is not clear whether the cycle is the one recovered by the police with the IED intact after it failed to explode and whether they released the photo to the media. If so, the inclusion of this photo in the e-mail is not significant. If not, it is.

If the cycle figuring in the photo is found to have been used and successfully activated, that would be an indication that an organisation of Indian Muslims hitherto unknown to the police has been operating undetected.

In this connection, please refer to my following comments in my article on the November blasts in UP:

It has been reported that an e-mail message purported to be from 'Indian Mujahideen' received by some television channels before the explosions indicated that these explosions were about to take place.

However, it referred to explosions in two and not three cities. 'Indian Mujahideen' does not refer to any organisation, but it refers to Indian Muslims in general and says that the Indian Muslims have decided to take the offensive and wage a jihad.

In justification of this decision, it refers to the severe penalties awarded to the accused in the Mumbai blasts of March 1993, and the lack of action against Hindu police officers, who committed atrocities on Muslims. It also refers to the Gujarat riots of 2002 and the recent assault on arrested Jaish-e-Mohammad suspects by some lawyers.

The message is not only a warning of their intention to act, but also an explanation of why Indian Muslims have decided to act. The main point, which the sender of the message has sought to convey, is that the criminal justice system treats the Muslims severely, but is lenient to the Hindus.

The language used is typically Indian, the context and arguments used are typically of Indian Muslims and the issues raised are those which have been agitating the minds of sections of Indian Muslims like the demolition of the Babri Masjid in December 1992, lack of action against the Hindu police officers of Mumbai who were found guilty of excesses by the Srikrishna Enquiry Commission, the severe penalties awarded to Muslims who had retaliated in March 1993, and the Gujarat riots.

It admits that the Muslims were responsible for the explosions in Varanasi, Delhi, Mumbai and in a restaurant and park in Hyderabad, but says they were not responsible for the blasts in Malegaon in September, 2006, on the Samjhauta Express and the Mecca Masjid of Hyderabad this year (2007). It is silent on the recent blast in the Ajmer Sharif, a Muslim holy place famous for its tolerant Sufi tradition.

It says that the Indian Muslims have decided to wage a jihad for Islamic rule and talks of a 'war for civilisation.' It warns that their next targets will be police officers.