According to an official of the Nandanvan Police Station, the incident occurred at around 1.30 a.m. in the city's Aradhna Nagar area.
"According to preliminary investigations, they were attacked and killed by some sharp weapons as they slept. There were no signs of struggle or robbery. The bodies have been sent for autopsy," the official said.
The victims have been identified as Kamlakar Pavankar, 45, his wife Archana, 40, their daughter Vedanti, 12, a nephew Ganesh Palatkar, four and grandmother Mirabai, 70.
Pavankar was a realty dealer and a local BJP activist. He also ran an electronic spares shop.
Besides, he had another shop on rent and owned a 10-acre plot on which some disputes were going on, and police said they would probe all angles including business rivalry.