A tapped conversation of a call made by a Thuraya satellite phone number 008821621523999 was the first breakthrough for the Delhi police investigating the serial bomb blasts that rocked Delhi on the eve of Diwali in 2005.

Here is the recount of the police investigations into the blasts. The blasts took place at crowded areas of Sarojini Nagar market, Paharganj and Kalkaji killing 50 persons and injuring 104 on October 29.

Since Prime Minister Manmohan Singh [Images] and President Pervez Musharraf [Images] have agreed to tackle terrorism jointly the investigations of such cases assumes a greater significance as Dr Singh himself recently said that Pakistan "will now be put under the test."

The devastating RDX

The bomb blast in Sarojini Nagar market was so intense that an eyewitness told the media, "It was like people in flames walking all around us -- their clothes were torn off. Women and men were walking in a daze in a semi-nude condition with burn injuries all over their bodies. All that we shopkeepers did was to wrap bedsheets around the victims."

The first thing the Delhi police officers who rushed to the shop number S-21, Shyam Juice Corner, where the bomb was kept, found that the blast was unusually deafening and devastating. One of the investigators said, "The Improvised Explosive Device contained high explosives which were triggered by a time-delay mechanism."

Laboratory tests proved that RDX was used to inflict maximum damage. In New Delhi, which predominantly follows Punjabi and north Indian festive traditions, Diwali is the biggest event of year.

In view of the sensitivity of the event, the government transferred the blasts cases to a Special Cell headed by Deputy Commissioner of Police Ajay Kumar. The cell handles serious crimes, terrorism and counter-terrorism cases. Ajay Kumar used the Delhi police's 'cyber cell' that investigates cyber crime.

After the blasts, a massive operation was launched to track down the conspirators, executors and abettors of the crime. An extra-ordinarily high number of cellphone conversations were intercepted.

The Delhi Police's 'Lawful Interception Center' which works in the backyard of a senior policeman's office went through thousands of intercepted conversations but they could not find any clue to the blasts.

When Abu al Kama dialled Tariq Dar

However, the Intelligence Bureau, India's internal intelligence agency, succeeded in less than a week, claims the police.

If one believes the claims made in the charge-sheet filed by Special Cell the Thuraya satellite phone number 008821621523999 was used by the prime accused in the case Abu al Kama, a Lashkar-e-Tayiba operative. The Lashkar is a Pakistan-based terrorist organisation operating in Jammu and Kashmir [Images].

As a regular exercise hundreds of telephone numbers belonging to suspect Kashmiri militants were intercepted and the government records thousands of phone conversations. A large part of the job is conducted by the IB and the Research and Analysis Wing, India's external intelligence agency. Almost all terrorist groups telephone numbers known to the intelligence agencies are kept under surveillance.

According to a senior police officer, who was part of the investigation team, "The interception by IB gave us the first definite clue that the blasts were related to the Kashmir issue and that the LeT was behind it."

On November 1 and November 4 last year two conversations were intercepted which set the pace for the investigations.

Kama twice called an Airtel mobile number 9906719815 in Jammu and Kashmir. It was traced to Tariq Ahmed Dar, an employee of the multinational company Johnson & Johnson. He is a science graduate and was living at 33, Solina Bala area near Rambaug in Srinagar [Images].

A forensic test proved that Tariq's voice matched that of the intercepted conversation. Tariq was arrested from the Pampore highway near Srinagar on November 10, 2005. Tariq was thoroughly interrogated and he is now an important accused in the blasts case.

In the one part of the conversation, submitted before the Delhi's chief metropolitan magistrate court in February 2006, Kama was telling Tariq, "...Delhi mai kuch bazaar aise hote hai jahan camera hai, jahan bande ki shankht vanakht sab hoti hai, lekin is wale jagah par koi camera nahin hai... koi kabuliyat wali baat na honi chahiye, ek baat to tay hai ki jimmedari ka to sawal hi nahin hai..." (In New Delhi there are some places where cameras are kept, guys will be recognised but in this place there were no camera. One thing is for sure there is no question of owning up responsibility).

In one part of the conversation on November 4, Tariq tells Kama, "...charon log aa gaye hai, idhar abhi aaj. Mujhe yakin hai, Insha Allah Taaroz kayamat ye baat udhar hee reh jayegi. Doosra, vo kehte hai ki who immediately aisa he dobara kar sakte hai..." (All four of them are back. They are right here. They are claiming that they can repeat the act.)

During some other conversation Tariq allegedly said, "Achcha main ne dubara repeat karaya hai, aaj vo GK hai, uska front page aap jaroor padhiye, internet per. Maine repeat karaya hai, bada tafselan..."  (I have got it repeated in the press. Do read the front page of GK on the Internet.)

Tariq Dar did it for Rs 5.5 lakh

However, while Tariq has admitted in court that he was involved with Pakistan-based terrorist groups in the hawala (money laundering) business he was not aware of their plans for the serial blasts in New Delhi. He insists that he had no direct links with the blasts.

Tariq told the Delhi police during interrogation that some years back when he was working with a magazine called Mountain Valley he came in touch with a reporter named Javed Ahmed Sheikh, who was living in downtown Srinagar. Javed introduced him to a terrorist outfit. Tariq claims that the lure of money attracted him. He agreed to get 'active' after Javed introduced him to a 'senior' LeT militant Abu Ozefa, a Pakistani national operating in J&K.

Ozefa was divisional commander of the LeT in Kashmir. Tariq met him along with Javed in the Harwan forest near Srinagar. When Tariq became a medical representative for Johnson & Johnson, Ozefa asked him to arrange for the treatment of terrorists because he knew the network of doctors and hospitals. Also, he was asked to work as a LeT spokesperson.

As he got more experienced, Tariq began raising and distributing money to LeT cadre in Kashmir. His hawala activities and his handling of blood money were well investigated by the Delhi and Srinagar police.

Tariq's official income was less than Rs 10,000 per month but he had accounts in HDFC Bank [Get Quote], State Bank of India [Get Quote] and Jammu and Kashmir bank. He was receiving foreign remittances including large amounts from Gulf countries.

According to documents filed by the Delhi police, credible evidence shows that Tariq Dar had deposited Rs 84 lakhs in his four accounts in a short period out of which Rs 26 lakhs were received from Gulf countries.

Tariq's role earned him trust in the higher-ups in the LeT. So, Ozefa arranged his meeting with Abu al Kama, who was using a satellite phone of Dubai based international telecom service provider Thuraya.

Ozefa also gave a Thuraya connection to Tariq but it was taken back immediately after the Delhi blasts.

Much before the blasts, Javed was killed in a police encounter in October 2004. Tariq was arrested and released on bail for having illegal foreign money in April 2005.

Interestingly, Tariq's work as spokesperson of LeT got him in trouble after the Delhi blasts. Tariq told the police he was given a new mobile number 9906719815 and told that he will be given instructions on whether to own up for the terrorist act or not by someone called Zaid from Pakistan.

From this mobile number Tariq was in constant touch with Kama and Ozefa's Thuraya numbers.

Operation Mansoor

Police also claims that in a meeting held during Ramzan of 2005, Tariq was introduced to a resident of Pakistan-occupied Kashmir named Mansoor and a Pakistani named Rashid. Both were operating from Sopore town in Kashmir.

The LeT's commander in Badgaum Sajjad Salfi, a Pakistani, and a local Kashmiri named Mohmmad Rafiq Shah were also present at the meeting that took place in presence of Ozefa.

Delhi police claims that in the meeting Ozefa complained that they are being pressurised from Pakistan to carry out some action. Thus was born 'Operation Mansoor' � the name of the operation to carry out serial blasts in New Delhi.

Mansoor, a LeT operative, took the responsibility of executing the blasts with help of Rafiq Shah and Mohmmad Hussain Fazili, a resident of Sarsayyad Colony in Srinagar. Both were formerly members of Hizbul Mujahideen.

Kama managed to smuggle RDX across the border but under Zaid's supervision RDX was brought to Delhi in a truck. The transport of RDX has been investigated in detail.

Police claims that Mansoor planted the bomb in Pahadganj, Rashid and Salfi planted bombs in Sarojini Nagar while Rafiq Shah alias Mansoor planted the bomb on a bus at Kalkaji. Rafiq was doing his masters from SP College, Srinagar. A special cell team arrested him on November 22 in Srinagar.

Shah alias Mansoor's sketch was prepared by help of an eyewitness who was travelling in the bus. The eyewitness's name is kept secret and he has been hidden in a safe house.

When the police further investigated the origin of Mansoor's mobile they found that his mobile was running on a parallel mobile number 9419449528 having same registration IMEI number (The International Mobile Equipment Identity is a 15-digit Code used to identify the GSM/DCS/PCS phone to the network) 356207007579668. That was traced to Mohmmad Hussain Fazili and that's how he came into the police net.

His interrogation revealed that he first joined Al Jehad after getting influenced by sermons at his local mosque. He claims that he got training to handle weapons in the mosque too. In 1997, he joined the Hizbul Mujahideen and went to Pakistan for further training. He was arrested and jailed for two years. On his release, he joined the LeT and was asked to take part in planting the bombs in New Delhi. For some reason he did not reach Delhi.

After the blasts, Tariq called Kashmir News Agency on behalf of LeT and planted a story that LeT was not behind the blasts in Delhi. He also called the BBC office in Kashmir from his mobile and repeated the same under the assumed name Abu Haniffa.

The conversations above between Tariq and Kama corroborate police findings that Tariq called Greater Kashmir to deny LeT's hand behind the blasts. Mohammed Rafiq Shah alias Mansoor who planted bomb in a bus at Kalakji was using mobile number 94194-75249. Police have found reliably that Tariq and Mansoor were also in touch after the blasts. According to Rariq's statement, Kama promised to give Rs 5.5 lakh to Tariq for the Delhi blasts.

Tariq Dar, Mohmmad Fazili and Mohmmad Rafiq Shah have been arrested and made prime accused in the case. Tariq and Rafiq Mansoor's narco-analysis proves that they took part in the Delhi blasts.

Ozefa was killed in a police and army's combined operation in Kashmir on January 17. Kama is at large and is thought to be hiding in Pakistan, claims investigators. And he is probably using a new Thuraya number.