A 45-year-old woman, who was separated from her husband, was found dead in her sister's house in Vasundhara area on Thursday, police said.
Police said the victim, Sunita Singh, was the estranged wife of Satyvir Singh. She had been living with her younger sister Vineeta Singh, employed with Delhi Police's women's cell, in Sector 2, Vasundhara.
The death was discovered by Vineeta when she returned from office on Thursday and found her sister lying motionless in bed. She then informed police.
"Sunita had been strangulated," said Circle Officer R.K. Pandey.
Two years ago, an attempt had been made on the life of Sunita. Following the attack, she had left her husband's house and sought the safety of her sister's home.
According to sources, Sunita's husband and adopted son had been exerting pressure on her to transfer the house she owned in Maliwara to them, but she had refused.
Vineeta indicated to police that she suspected the duo's hand in her sister's murder.
"A case has been registered. Investigations have begun. We shall crack the case soon," said Superintendent of Police (City) Shiv Shankar Yadav.