Shyamal Karmakar was nabbed from Rampurhat station in Birbhum district Tuesday night, North 24 Parganas district police superintendent Tanmay Roychowdhury told mediapersons.
Karmakar is said to be the kingpin of the group which lynched Sourav Chowdhury and chopped his body before throwing the parts onto the railway track between Duttapukur and Bamangachi stations of North 24 Parganas district last week.
Chowdhury's dismembered body, found Saturday morning, has created outrage across the state.
With Karmakar's arrest, the total number of those rounded up by the police has risen to nine.
Roychowdhury said police got tip-offs about Karmakar's hiding places by questioning his close associates arrested over the past few days.
He would be produced in court during the day.