Two letters, purportedly exchanged by Maoist leaders, indicated plans to assassinate Prime Minister Narendra Modi, BJP President Amit Shah and Home Minister Rajnath Singh, leading to police action against prominent left-wing activists in several states and the arrest of five of them for suspected links with the Maoists, security officials said.
While a letter from 2016 suggested that there were deliberations among the maoists to kill PM Modi, Mr Shah and Mr Singh, a letter from 2017 referred to a plan to carry out a Rajiv Gandhi assassination-type attack on the Prime Minister during one of his roadshows, they claimed.
The second letter was addressed to a "Comrade Prakash" and was found from the residence of a Delhi-based activist, Rona Wilson, on June 6, according to a security official privy to the development.
Along with Rona Wilson, four others were also arrested during raids in June by police in different parts of the country in connection with the matter.
The letters were reportedly recovered after anti-naxal operations in Maharashtra's Gadchiroli, in which 39 were killed, in April.
The 2017 letter also referred to "senior comrades suggesting concrete steps" to end the NDA dispensation and about raising several crore of rupees to buy American M-4 rifles and some ammunition, the official said.
Tuesday's police action started at 6 am and was carried out simultaneously by Maharashtra Police, led by Joint Commissioner of Pune, Ravindra Kadam, in Ranchi, Goa, Delhi and Hyderabad.
Five persons have been arrested so far, another official said.
Searches were carried out at the residences of Arun Ferreira, Susan Abrahams and Vernon Gonsalvez in Mumbai, Gautam Navlakha in Delhi, Anand Teltumbde in Goa, Varavara Rao's daughter Anala and Journalist Kurmanath in Hyderabad.
During the searches, police also confiscated several items like computers, laptop, CDs, papers and books.