The Forensic Science Laboratories of Agra and Ahmedabad have detected the use of RDX and some other substances,including nitrate,in December 7 blast at Sheetla Ghat in Varanasi. An infant girl and a woman were killed in the blast. Officials from the Uttar Pradesh Anti-Terror Squad (ATS) said the FSL report has not provided any clue that could help the investigation. They don’t even know how the blast was triggered.