Bongaon: Four friends of an engineer who drowned in a water body in Gaighata, North 24-Parganas, two days ago were arrested on Wednesday based on his family's murder complaint.

The body of Argha Mukherjee, 34, was fished out of the pond at Sonatikari in the Gaighata police station area on Monday afternoon.

Mukherjee's family lodged a complaint with the police station, accusing his friends of murdering him, on Tuesday.

Mukherjee, a Sodepur resident, had a BTech degree. He left home on Monday for his workplace, a battery manufacturing unit in Shyamnagar near Naihati, police said.

"But he reached the banks of the water body with the friends from Sodepur and Shyamnagar," an officer of Gaighata police station said. "Residents of the area told us that they saw them drinking and chatting before suddenly raising the alarm that Mukherjee had slipped into the water."

Residents fished the body out of the water in the afternoon.

Mukherjee's family claimed he knew swimming and that is why it was unlikely that he would drown, the police said.

"We have sent the body for post-mortem. There were no external injury marks on the body," an officer said.

The four arrested are Manish Das, Aloke Chakrabarty, Indrajit Biswas and Subhasish Mukherjee.

Man attacked

A 42-year-old man was injured when a youth and his friend attacked him with a knife in Liluah, Howrah, on Tuesday.

Tapan Mondal went to Ramesh Bag's house after he found out Bag was having an affair with his wife, police said.

Mondal alleged Bag and his friend attacked him, the police said. Mondal was admitted to a health-care unit with injuries on his neck and hands.