The Jharkhand police have questioned over two dozen residents of a village in Jamshedpur in connection with the killing of Jharkhand Mukti Morcha member of Parliament Sunil Mahato.
"We have been interrogating the villagers of Baguria regarding Mahato's killing, but did not detain anyone," Deputy Inspector General of Police (Kolhan) Ramlaksham Prasad said.
Detention would be made if any concrete evidence was found against someone, he said.
The investigation was moving in the right direction and a breakthrough is likely to be achieved soon, Prasad said.
He said no restriction was imposed on the movement of villagers of Baguria, about 40 km from Jamshedpur.
Maoists shot dead the MP, his bodyguards and a party colleague during a football match at Baguria on the occasion of Holi.
Meanwhile, a combing operation was jointly launched by the East Singhbhum district police and their West Bengal counterparts in the bordering areas of Ghorabandha and Dumria in the Naxal-infested Ghatshila sub-division to flush out the ultras.
The operation was being led by Superintendent of Police, East Singhbhum district, Pankaj Darad. Senior police officials were currently camping in Ghatshila.