The National Investigation Agency arrested TMC leader Chhatradhar Mahato in connection with the killing of a CPI(M) leader in 2009, soon after he cast his vote in Lalgarh during the first phase of polling in West Bengal, a senior official said on Sunday.

Mahato, the former convenor of the Maoist-backed People Against Police Atrocities (PCPA), was nabbed from his residence in Jhargram district by an NIA team comprising of 40-45 personnel late on Saturday, hours after he exercised his franchise.

"He was arrested in connection with the 2009 killing of CPI(M) leader Prabir Mahato. He has been booked under the Unlawful Activities (Prevention) Act. We will produce him at a city court on Sunday," the NIA official said.

The Calcutta High Court had recently directed Mahato to appear before the NIA thrice a week to assist it in investigation of the case.

Mahato, 50, had earlier served a 10-year sentence for his involvement in a landmine blast triggered by Maoists in Salboni in 2008, aimed at the convoy of the then West Bengal chief minister Buddhadeb Bhattacharya and former Union minister Ramvilas Paswan.