The deceased was identified as Lakhsmi, wife of a Central government official, who lived at the CPWD quarters in RK Puram Sector 1 with her husband and 25-year-old son.
Her son Avinash had come home at around 3.30 pm for lunch and when his mother did not open the door he broke open and found Lakshmi's charred body and raised an alarm, said police.
Lakshmi's husband A C Shivshankar was in office, when the incident took place. The family is a native of Tamil Nadu and has been living at the quarters for around five years, said police.
"It was surprising that the woman was burnt to death and the neighbours did not even hear a scream," said an official privy to the investigation.
Her body has been sent for a postmortem examination, police added.