The Central Bureau of Investigation has arrested an activist of the Maoist-backed People's Committee Against Police Atrocities from a village in Jhargram in connection with the Gyaneswari Express derailment, the police said on Tuesday.
Hiralal Mahato was produced in the additional chief judicial magistrate's court after his arrest on Monday.
Mahato is a resident of Rasua village near Sardiha, the site of the train derailment.
148 people were killed when the Jnaneswari Express derailed on May 28.
The police had on June 4 seized a pickup van, claimed to have been used to ferry men who sabotaged the railway tracks leading to the derailment.
The husband of the vehicle owner was arrested and remanded in police custody for 10 days. The van was registered in the name of Chhabi Mahato, a former CPI (M) panchayat member of Sardiya. Her husband Khagen Mahato was arrested by CID sleuths from Kharagpur town in West Midnapore district.
According to CID sources, Mahato had used the van to ferry the saboteurs to the railway tracks at around 10 pm on May 27, hours before the disaster.
A mobile phone from which Mahato made a number of calls that night was also seized, they said.The saboteurs, including PCPA members Bapi Mahato, Manik Mahato, Umakanta Mahato and some others had held a meeting at a Shiva temple at Muramoni to firm up their plans, the sources said.