However, Sudhakaran denied the charges and said he had done nothing wrong and was ready to fight legal battle.
The case against the sitting MLA, who is seeking his electoral luck again from Ambalapuzha constituency, was registered based on the direction of Chief Electoral Officer E K Majhi, police said.
Congress' district committee president A A Shukkoor had lodged a complaint with the Election Commission demanding action against Sudhakaran for violating electoral rules.
Sudhakaran, along with Achutanandan's son Arun Kumar, was standing very close to the voting compartment when the marxist veteran was casting his vote.