Chilla Satyavathi was allegedly smothered to death by the accused persons, who later made away with her gold ornaments on February 14, police said.
The former corporator was found dead in her room of a three-storeyed building in Alipuram area of the city.
"Satyavathi's tenant, his wife and their juvenile sons aged 10 years and 17 years have been arrested in connection with the crime," said DCP (Law and Order) Navin Gulati.
He convinced the old lady that his youngest son would give her company during night as she was alone, said the DCP.
On the day of the murder, the accused gave a cell phone to his son and told him to call him up once Satyavathi was asleep and also open the door from inside, said the officer.
All the family members entered the room after the child opened the door and smothered Satyavathi to death and escaped with four bangles and a gold chain, said police.