Jyoti, 30, was stabbed by her 27-year old brother, Mohinder, in south Delhi's R.K. Puram area, police said.
The incident took place around 3 a.m. Wednesday in R.K. Puram's sector 3.
Police said Mohinder, who was jobless, himself informed them of the incident.
"Since Mohinder also had some bruises on his body, he was taken to a nearby hospital. After being given first aid treatment, he was taken into police custody," a police officer said.
A property dispute was not being ruled out, he added.
