Nagpur, April 30 -- Panic gripped parts of Nagpur after an anonymous letter claimed that radioactive material had been placed at the Rashtriya Swayamsevak Sangh (RSS) headquarters in Mahal and the Dr Hedgewar Smriti Mandir in Reshimbagh, triggering a multi-agency security response and city-wide inspections.

The letter, written in English and addressed to Police Commissioner Ravinder Kumar Singal, was received by post on April 27.

It stated that the letter was sent by an organisation named "DSS," and also contained objectionable language against the RSS. The letter caused a stir, and the ATS launched a thorough investigation at all locations, Police said.

The sender alleged that a radioactive substance, Caesium-137, had been dispersed at ...