Krishnagar, May 9: A CPM zonal committee member in Nadia was arrested from North 24-Parganas last night in connection with the murder of three traders at Hanskhali, about 60 km from Calcutta, a fortnight ago.

Dulal Biswas was using his friend’s house in Barasat as a hideout after allegedly engineering the triple murders, said police. All three victims were CPM supporters.

A team led by the officer-in-charge of the Hanskhali police station, Saugata Roy, picked up the member of the CPM’s Hanskhali zonal committee from the house at Chapadali More.

Six others, including Biswas’s son Bappa, were taken into custody earlier.

All seven were produced in Ranaghat court today and remanded in police custody for a week.

Nadia superintendent of police R. Rajshekharan said Biswas went into hiding soon after the traders were shot dead. ?Relatives of those killed ? Krishna Biswas, Purna Adhikari and Panchanan Sarkar ? have alleged that Biswas was the mastermind of the killings,? he said.

The CPM leader is believed to have plotted the attack to ?ensure punishment for his brother Swapan’s killers?. A gang had gunned down Swapan in much the same manner on January 27.

The trader trio was apparently trying to arrange bail for their relatives arrested in connection with Swapan’s murder. Those held included Sasanka Biswas, a former Congress legislator.

Rajshekharan said the traders were trying to mobilise witnesses to get the murder accused out on bail before the trial began.

A senior district police officer said Biswas had cautioned the trio against working for the rescue of his brother’s killers. ?But they turned a deaf ear to his warning.?

The police suspect that Biswas possessed illegal arms. The officer said raids would be conducted on several other places and Biswas and his associates questioned on the arms.

Nadia CPM secretary Ashu Ghosh said: ?A committee will be formed to inquire into Biswas’s alleged involvement in the murders. The party will not shield him. The law will take its own course.?