The deceased has been identified as Urmila, they said.
The other four injured include Urmila's three children Priyanka, Devilal, Raj and one Mahendra Kumar, police said.
They all were rushed to a government hospital in a serious condition, they said.
The incident happened during the wee hours of the morning when Urmila was sleeping with her family in her house at 23 BB-Bera village when the fire broke out, they said.
A case under section 302 IPC (punishment for murder) has been registered on the basis of complaint filed by Urmila's family against Mahendra, who is also believed to be Priyanka's boyfriend, police said.
Mahendra works in a thermal station at Suratgarh and he lives just 1 kilometre away from the fire site, the police said, adding that he would be arrested after he is discharged from hospital.