The robbers began chasing the woman from the Sarita Vihar underpass and managed to lift her bag at the Ma Anandimayi Marg.
Two country-made pistols, five live cartridges, and a car with a fake number plate was also recovered from their possession.
The accused have been identified as Ramanjeet Kaur, a resident of Nangloi and Ramneek Singh (24), a resident of Nihal Vihar. They are the member of alleged Bunty-Babli gang, police said.
The 19-year-old was taken to Babu Jagjivan Ram Memorial Hospital where he was treated for his abdomen injury.
The accused were identified as Yash Kumar (19), a resident of Ashram and Deepak (23), a resident of Lajpat Nagar, police said.
The deceased, Nathia, a resident of Pitampura, was missing since Sunday, following which her son Babu Ali filed a missing report at the Maurya Enclave police station, the police said.
Police said they had parked the car near the mall and the man went out to relieve himself. After he returned, two bike borne men came and knocked at the car window and asked him for an address.