Two labourers were electrocuted at an under-construction building site in Kalikapur in the Kasba police station area in South 24-Parganas on Saturday.
The deceased have been identified as Sannnyasi Pramanik (28), a resident of Sonarpur and Jiben Saha (22), a resident of Falta.
According to the police, a water-filled reservoir at the construction site came in contact with some naked wires.
Sannyasi got into the reservoir and was electrocuted, while Jiben lost his life in a bid to save him.
A senior official in Kasba police station said the police have registered a suo motu case against the promoters concerned.