Aravindan (45) was at his fish farm in Panur in the district when six men attacked him with wooden logs fitted with nails and fled, the Kannur Special Branch police said.
His left leg was broken in the attack which took place around 8.00 pm. He has been admitted to the co-operative hospital in Thalassery for treatment, police said.
Aravindan had switched over to the CPI(M) from the BJP two years back, they added.
Though police suspect the involvement of BJP activists in the attack, they said details could be known only after an investigation which is now being carried out.
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