Sita, a resident of Hanumangarh in district Bhiwani, died Sunday night at the hospital.
Dharmveer who was also badly burnt in the incident is still under treatment.
An FIR with charges of murder has been registered against the constable at Sector 65 police station, police said.
According to police, Sita stayed with her husband and a seven-year-old daughter in a government quarter at CRPF camp, Kadarpur.
On July 17, after a heated argument between the couple, the constable allegedly set her ablaze after pouring some inflammable substance.
They were both burnt badly in the incident, they said.
They were first rushed to a private hospital in Gurgaon, and were later referred to Delhi, AIIMS.
Sita died during treatment on Sunday late night while her husband was still being treated, police said.
On Monday, Karmchand, Sita’s brother filed a complaint in which he accused his brother-in-law for his sister’s murder.
“On July 17, there was a dispute between them and Dharamveer lost his temper on some issue and set my sister on fire by pouring inflammable substances on her. After this the neighbours gathered who doused the fire and admitted Sita to a hospital but she died on Sunday night,” PTI quoted the complainant as saying.
“As per the complaint, an FIR has been registered. The accused is under treatment. Further action will be taken as per the law,” said Vinod Kumar, SHO of Sector 65 police station.
With PTI inputs