Digital forensic engineer and consultant Prashant Pandey approached the SC last year for a CBI inquiry into the rampant use of illegal software to tap phone conversations and obtain call data records (CDRs). The software, his petition claimed, was available to anyone who could pay, and he alleged that government agencies had acquired the software for Rs 5 lakh-Rs 50 lakh paid monthly to a US firm. He spoke to Uttam Sengupta. Excerpts: