The couple was attacked around 9 pm on Sunday when they were sitting in a park in Delhi.
A 56-year-old woman died and her husband was injured when they were attacked by unidentified assailants in a park in west Delhi, police said on Monday.
The couple was attacked around 9 pm on Sunday night when they were sitting on a bench in a children's park in Prashant Vihar area, police said.
The couple has been identified as Kulbhushan Bhutani, 60, and Kanchan Bhutani, who resided in Laxmi Kunj apartment, police said.
According to a senior police officer, the couple was attacked from behind on the neck with a sharp weapon.
"Kanchan Bhutani was declared brought dead while her husband was admitted to hospital with major injuries around his neck," the officer said.
"His condition is out of danger," the officer added.
"At the time of the attack, there were a number of people in the park, but everything happened so suddenly that nobody got the time to react," the officer said.
Mr Bhutani used to run a business of cables. "It is too early to comment on the motive behind the murder," the officer said.
The officer, however, refused to comment on the number of attackers or reason for the attack, saying they are looking for the CCTV footage of the area to get some clue.
No items or cash were stolen from the couple, police said.
Police said the family of the couple had gone to watch a movie on Sunday evening.
A case was registered against unidentified persons and investigation is underway, the officer added.
This is the sixth case of attack on an elderly couple in the national capital in the last one month. In four cases the role of domestic helps was found.