India, Feb. 6 -- A day after three sisters jumped to their death from their ninth-floor home in the Sahibabad area here, residents of the residential complex were in shock, pondering how the girls' prolonged seclusion had gone unnoticed.

Residents of the Bharat City Society were seen huddled in small groups within the premises on Thursday, discussing the tragedy and the effects of online addiction on impressionable young minds. "It is very shocking. One can understand if someone takes such an extreme step owing to depression. But how could all three sisters do this together?" wondered Isha Tyagi, a resident.

The woman said she had never seen the girls going to school or playing in the society park with other children. Their isolation ha...