Investigations have revealed that ASI Sheshnath Singh provided prior information about the movement of Munda to Naxals, who then attacked and killed him, an NIA spokesperson said here.
Singh has been sent to policy custody till October 15, he said.
The NIA teams are also conducting searches at four locations in Ranchi today in connection with the case, the spokesperson said.
Munda, who was a Janata Dal (U) MLA, was killed allegedly by Naxalites when he was delivering a speech at a function in Bundu in his assembly constituency Tamar on July 9, 2008.
His two bodyguards were also killed in the attack.
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