At least 20 terrorists were involved in preparing and carrying out the three serial blasts that killed 59 and injured about 210 in Indian capital on Oct. 29, local media reported Friday.
Friday's Hindustan Times quoted the police source as saying that, according to the initial investigation, the police found at least 20 terrorists were divided into four groups to carry out separated tasks for the serial blasts.
Each of the four groups might not know what others would do so that the police would have not established any link if any one of them had been caught, the police said.
The first group brought explosives to Delhi while the second group was in charge of assembling them. Another group would have been made up of experts skilled in fitting electronic timers and giving explosives the final shape. And the last group would place the bombs on the selected sites and explode them.
The police source said the last group might consist of green hands since in two of the three blasts, eyewitnesses said the bombers panicked and fled from the spot.
The police believed the explosives used in the blasts had been shipped in Delhi three or four weeks before Oct. 29 and could have consisted of arms and ammunition.
Despite the initial report on the organization of the blasts, the police made little progress in tracking the suspects and identifying where they came from.
The sketches of three suspected bombers in the blasts were issued Wednesday, each of which looks obviously a Muslim young man in his early twenties.
The sketches put an innocent youth in trouble Thursday. Mohammad Nawab, 21, was beaten up by local residents in Vaishali area of New Delhi as he looks like one of the suspects. The police finally found out that the young daily-wager has nothing to do with Saturday's blasts.