Thodupuzha police registered the case in view of Mani's statement that CPI-M was behind some of the political killings in Idukki district in the 1980s, which the party has, however, distanced itself from.
According to police sources, Mani, who is CPI-M Idukki District Secretary, has been charged under IPC 302 (murder), 109 (abetment) and 118 (concealing design to commit offence).
State Home Minister Thiruvanchoor Radhakrishnan said the government would allow the law to take its own course.
After the party drew flak from all quarters, CPI-M state Secretary Pinarayi Vijayan yesterday openly censured Mani and said his statement was a "mistake and against the political line of the party."
Senior leader V S Achuthanandan, against whom also Mani made some sarcastic comments during his controversial public speech at Thodupuzha, said his utterances on political murder should be rejected with contempt.
Achuthanandan, who was the party state secretary when the murders Mani referred to happened in Idukki District, said he could say with authority that it was not true.
Mani's speech has sparked a controversy with the Congress and BJP saying it exposed CPI-M's "politics of violence."
Mani had later clarified that he was only narrating the history of resistance put up by the party in the past during adverse political situations.
His statement had only added to the acute embarrassment of CPI-M in the state which is on the defensive with some of its activists being arrested in connection with the murder of party rebel and RMP leader T P Chandrasekharan at Onchiyam in Kozhikode district on May 4.
