Those killed were 28-year-old Girish from Gorakhpur, his five-year-old nephew and seven-year-old niece, while his sister-in-law was battling for life in a hospital, they said.
The gas from the cylinder had leaked during night as the family had forgotten to close the stove properly. When Girish switched on the light early this morning, it triggered a fire, Kodungayur Police Inspector D Baskaran said.
Hearing the screams for help, the house owner and others pulled them out and rushed them to Government Kilpauk Medical College Hospital.