Officers were called to a home in the 2300 block of Worthing Drive Wednesday for a well-being check when they found the body of Cathleen Lewis.
Police have told neighbors they do have some leads but nobody in custody.
According to the coroner's report, Lewis died from blunt head trauma due to assault. Police say there was no sign of forced entry into the unit and Lewis may have known her killer.
Officials also say there is no reason to be alarmed since they do not believe the crime is random.
Investigators went door to door Thursday looking for anyone who may have noticed anything that might help them determine who killed Lewis.
"Her mother was not able to get hold of her. So she contacted the Naperville police department to go and do a well-being check. Naperville officers discovered a female, white, inside the apartment and she was deceased," said Sgt. Greg Bell, Naperville police.
Most neighbors ABC spoke to said they rarely saw her.
"I understand that an older lady got beat. Why an older lady would get beat, there's really no probable cause," said Chris Nendick, neighbor.
Police say violent crime in the southwest suburb is rare.
"Overall I feel safe, but just being more vigilant and trying to watch the neighbors a little bit more," said Beth Griffith
"Is it upsetting...I don't know if it makes me personally nervous. I'm going to be more aware," said Reno Pirami.
Police say they are looking for the victim's brother, Mark Lewis, 51, of Lakemore. They have not been able to reach him to notify him of his sister's death. Officials say he's driving a green Ford Explorer.
Police say they have no history of any problems at Lewis' address.