Shajahan was standing on a road last night when the gang attacked him with sharp-edged weapons, killing him on the spot, they said.
Several cases, including three murder cases, were pending against him, police said adding they suspected gang rivalry behind his killing.
He was arrested by CB-CID police in August last for allegedly possessing deadly weapons. Later, the Special Investigation Division probing the killing of Ramesh interrogated him for his suspected role in the crime after which he was lodged in the central prison here.
Chief Minister Jayalalithaa ordered a probe into the murder of Ramesh and leaders of Sangh parivar units in the state following demands by the BJP, which alleged its leaders were being targeted in the state.