Khokan Das, 32, was arrested on Friday in connection with the twin murders committed in Kasba last week.

Khokan is the younger brother of Dilip Das, who had hosted the party at which the murdered duo was last seen. He was rounded up from his house in Kasba?s Bosepukur.

Friends Piyush Saha, 25, and Bimal Chakraborty, 28, went missing last Sunday evening. On Monday, residents of Kasba Prantik Pally discovered the two bodies by a canal.

Piyush had a bullet drilled into his head, a deep slash on the waist and his genitals had been chopped off. A few yards away, closer to the water, lay Bimal, with multiple stab injuries all over his torso and badly-damaged genitals.

They had told their families they were going to attend the birthday party of Dilip?s son. Both victims traded in readymade garments, as well as building material supplies.

Khokon, also a supplier of building materials and reportedly with links in the ruling party, was arrested after two days of interrogation.

?The murder could have been due to a property dispute or a triangular affair,? said S.N. Gupta, superintendent of police, South 24 Parganas.

Police are also interrogating six others, including Dilip, the slain duo?s host.

?Involvement of local people is suggested. No outsider would know the place where the bodies were dumped,? a sleuth said.