Vimla Manuj, 61, wife of retired General Manager of Railways Aashutosh Manuj, was strangulated to death when she was alone at her residence.
Domestic help Shashi and her neighbour Sonu were held for murdering Vimla, Shiv Shankar Yadav, SP City said.
Sonu wanted to marry Shashi's sister but was unable to do so due to financial crisis, he said.
Shashi hatched a conspiracy to murder Vimla for which she sought Sonu's assistance and lured him by assuring to share the looted amount, the police official said.
In her earlier statement to police, Shashi had claimed that on August 12 morning Vimla had asked to do cleaning work on the second floor of the house and when she returned on the ground floor she spotted her lying in an unconscious condition.