The suspected honour killing took place at the woman's house in the Hauz Qazi area, where her body was found around 4:30 am on Thursday, news agency PTI quoted police as saying.

The accused, identified as Abullah and Arib, were traced and arrested after police examined footage from CCTV cameras, Deputy Commissioner of Police (Central) M Harsha Vardhan said.

DCP Vardhan said that there were no signs of sexual assault.

Police said the accused suspected that after her divorce, she had an affair.

"They were suspicious over her activities and felt insulted, and planned to kill their sister," Vardhan said.

He said according to initial investigation, she was smothered to death. The exact cause of death will be known after postmortem, the DCP added

In another case, a body of a man in decomposed state with multiple stab wounds was found in a house in southwest Delhi's Dwarka, police said on Wednesday, adding that his wife was detained in connection with the matter.

Police suspect the man, Sachin, a call operator in a private company, was killed by his wife Kavya, who was detained later from Uttam Nagar.

Initial investigation suggested that Sachin was killed by Kavya on the intervening night of Saturday and Sunday due to regular domestic violence, the officer said.

"Sachin had married Kavya three years ago in a temple but would often indulge in arguments and fights. Sachin's body had multiple stab wounds," PTI quoted an officer as saying.