New Delhi: With preliminary evidence suggesting that the terrorists who attacked the Pathankot IAF base attack used the canal route of Ravi river and then passed Bamiyal village, there may have been a serious technical security lapse as the thermal imager located between two BSF posts was not working Sources said there is a 134-meter stretch between two BSF posts in Bamiyal, which is at the International Border (IB), where the thermal imager used by border guards is located and which was not functioning.The thermal imager’s recorder was not operational which means that if terrorists entered through this stretch on December 31, their movement would not have been recorded. Source said the Hand Held Thermal Imagers (HHTI) and battle-field surveillance radars, placed at spots without fencing did not pick up any signal.It is suspected that terrorists entered Bamiyal village in Pathankot from Shakargarh town in Pakistan before abducting Innova driver Ikagar Singh — who they killed — and then Gurdaspur SP Salwinder Singh to reach the air base.Sources also said the BSF unit posted at this outpost in Bamiyal, near Jammu and Punjab border, had been replaced just 15 days back and new personnel had joined from a Meghalaya unit. “There is a possibility that the new unit was not yet familiar though firmer conclusions can be drawn only after investiga tion and proof that terrorists did enter from here,” said an official.The same route was used by LeT terrorists in the Gurdaspur attack last year. This part of IB is also often used by drug smugglers and fake currency suppliers. “When the water increases in the adjoining canals of Ravi river, movement is often seen at this side of the border,” said an official.BSF DG D K Pathak gave a report to ministry of home affairs on Monday about infiltration by terrorists which led to the daring attack at the IAF base.Sources said BSF told the ministry of home affairs that “prima facie, they have not come across any breach at the border”.