The incident took place last evening when an explosive device went off at the residence of Harji Valmeki (38), killing him, his daughter Godawari (15) and two children from their neighbourhood- Ronak (3) and Nandani (8), SP (City) Prafful Kumar said.
Another of their neighbour Santrabai (55) was severely injured in the blast and undergoing treatment at MBS hospital, Kumar said.
According to eyewitness, Harji was beating the device with a hammer outside his residence when it blasted, killing four on the spot, the SP said.