Mr Chandrasekharan had sustained 51 hack injuries on his face at the time of his death.
The Kozhikode Special Additional Sessions Court has found 12 people, including a seven-member gang and three CPM leaders, guilty in the TP Chandrasekharan murder case.
The quantum of punishment will be announced later.
Mr Chandrasekharan was hacked to death in May, 2012. He was the president of the Revolutionary Marxist Party or RMP in CPI(M) stronghold of Onchiyam in Kozhikode after he was expelled from CPI(M).
Mr Chandrasekharan had sustained 51 hack injuries on his face at the time of his death. The prosecution had argued that the leader was killed after being hacked to death by the seven-member gang, which was hired by the CPM.
Initially, there were 76 accused against whom chargesheet was filed, but the number was later dropped to 36 after the court had stayed the trial of 15 accused. Twenty two people were acquitted for lack of evidence, including former CPM Kozhikode District Secretary.
Mr Chandrashekharan's murder became a reason for public rift within the CPM leadership. While Opposition leader VS Achuthanandan has hailed him as a brave communist, CPM State Secretary Pinarayi Vijayan slammed him as a traitor.
The case had 166 witnesses of which 52 turned hostile.