New Delhi, Feb 20 (UNI) After conceding the 'explosives' that rocked the Samjhauta Express were 'boarded' in Delhi, the Special Cell of the Delhi Police is concentrating on guest houses and hotels in Old Delhi and Paharganj area to nab the suspects involved in the blasts.

Besides the petrol bomb, investigations have revealed the presence of potassium and sulphur to enhance the lethality of the explosions, giving the probe an added dimension, said a senior Special Cell official.

''We have prepared a list of the suppliers of the substance and are moving accordingly.'' Despite the Haryana Police not having made a 'formal request' to us to join the probe, based on the sketches released we are moving ahead to nab the culprits as it is almost certain that the explosives, materials and devices used to cause the blasts had been kept at the Old Delhi Railway Station, he said.

''Presently the scanning of visitors, of the last few days, in hotels and guest houses around Old Delhi Station, Paharganj and its vicinity, are being done. As installing CCTVs is mandatory, we are trying to match the sketches released with them.'' A systematic methodology was being adopted to unravel those behind the blasts and hope to come out with something substantial soon, he added.

Another officer involved in the investigations said the team was as of now drawing the 'sequence of events' so as to go into the genesis of the blasts.

''As we had very less time to talk to the other passengers of the train, before they left for Pakistan, we are trying to piece together the information and draw a board chart which could then set the strategy to probe the case.'' But we are very much on the 'right track', he added.

UNI