Subhankar Sikdar (35) and Govind Sarkar (28) were arrested near Regal Cinema in Colaba on Friday, police said.
Police said that, on May 7, the two had entered into an argument with the victim in Cooper's Camp area of Ranaghat in West Bengal's Nadia district.
The two assaulted the 64-year-old woman and rendered her unconscious following which the two accused allegedly raped her, police said.
"After killing her, the two fled to Mumbai on May 10," said Sukhlal Varpe, Senior Inspector of Mata Ramabai Ambedkar Marg police station.
He added that the two were produced before a court which remanded them in police custody, Mr Varpe said.