The National Investigative Agency on Saturday began its inquiry into an explosive substance being found inside the Uttar Pradesh Assembly on Thursday evening. Officials told IANS that a team of NIA sleuths had arrived at the Vidhan Sabha late on Friday and had been briefed about the case.

NIA officials arrived at the scene on Saturday with sniffer dogs. The team is likely to question security staff and the state police assigned to ensure security at the Assembly.

Security has been tightened at the Uttar Pradesh Assembly since plastic explosive pentaerythritol tetranitrate was located inside the Vidhan Sabha. A packet containing the white powder was found under Samajwadi Party MLA Manoj Pandey’s seat.

PETN is a high explosive substance that can pass through metal detectors because of its plastic nature.

The Uttar Pradesh Police had filed an FIR against unknown persons in connection with the case on Friday. Inspector General (Anti-Terrorism Squad) Aseem Arun said they suspected terrorist hand in the act.