Noorjahan Gilani, the woman who sustained 90% burns on Wednesday died on Monday while undergoing treatment at Nair Hospital.
Following her death, the Malabar police have now booked her husband Gaus Gilani for murder under section 302 of the Indian Penal Code. Gaus had earlier been booked for attempted murder.
"Gaus is yet to be arrested. He is still undergoing treatment at the Nair Hospital. He has now been booked for murder. We will arrest him as soon as he is discharged from the hospital," said Prakash Malve, assistant police inspector of Malabar Hill police station.
According to the police, in the early hours of Wednesday, Noorjahan and Gaus got into a fight after the latter began assaulting his son Muzambil, 6, for not going for his tuitions. When Noorjahan intervened Gaus assaulted her, the police added.
A few minutes later, neighbours saw flames coming out of their residence located in Simla Nagar slum area of Malabar Hill, the police said.
Earlier, the police thought Noorjahan set herself ablaze and Gaus and their two children tried to douse the fire with their bare hands and also sustained burns. However, Noorjahan told the police that her husband had set her on fire.
Based on her statement, the police booked Gaus for attempted murder, which has now been changed to murder. The couple's two children, Mehrun, 11, and Muzambil have also been admitted in hospital.
While Gaus works as a plumber, Noorjahan was a housewife, the police said.