The victims were identified as Madhavi (30), her husband Babu Rao (35) and their son Laxman (10), Patancheru police station sub inspector N Venkatesh said.
The incident had taken place on April 16 in which the trio sustained serious injuries and were shifted to Gandhi hospital Secunderabad, he added.
They succumbed to their injuries this morning. The two other sons of Madhavi and Babu Rao identified as Manoj (12) and Sriram (10) who had also sustained injuries are undergoing treatment at the same hospital.