Central intelligence agencies will interrogate 'Waris Punjab De' chief Amritpal Singh, who was arrested by the Punjab Police on Sunday and later sent to Assam's Dibrugarh jail.
Chief Minister Mamata Banerjee, soon after the Burdwan blast, had blamed the Research and Analysis Wing (RAW), the foreign intelligence agency of India, for being behind the blast.
Intelligence reports suggest that the terrorists may enter India through Nepal or Bangladesh border and carry attack in Delhi, Ayodhya, Bodh Gaya or major cities in West Bengal.
The National Intelligence Grid or NATGRID is the integrated intelligence grid connecting databases of core security agencies of the Government of India. It collects comprehensive patterns of intelligence that can be readily accessed by intelligence agencies.