Interrogation of the accused also revealed that one of them was involved in an earlier rape-and-murder case, police said.
Arvind Baban Deshmukh (29) and Santosh Baban Chinchole (26) were arrested by Govandi police here. Deshmukh was arrested from suburban Kurla, whereas Chinchole was arrested from Malkapur in Buldhana district of Maharashtra.
Parvati Pandharinath Tandel (82) was attacked by unidentified persons at her house in Govandi area here in the wee hours of March 24. Her grandson found her lying in a pool of blood in the morning; she died at a civic hospital on April 14.
The duo confessed to killing Tandel when she resisted robbery, while Deshmukh also confessed to raping and murdering a 54-year-old woman in Deonar earlier, police said. Further probe was on.