Police are searching for the killer of 59-year-old Cathleen A. Lewis, who was found dead in her Naperville townhouse after being struck several times on the head, authorities said Thursday.
Police also are looking for the victim's brother, Mark Lewis, 51, of Lakemoor, in conjunction with their investigation, Naperville Sgt. Gregg Bell said.
Mark Lewis is not a suspect, Bell said, but officials are "concerned" because family and friends have not heard from him in several days and would like to notify him of his sister's death.
Lewis was last seen driving a green, 1999 Ford Explorer with a license plate reading 7758696.
Bell said police received a call around 6:10 p.m. Wednesday from Cathleen Lewis' mother requesting a well-being check for her daughter at the home on the 2300 block of Worthing Drive.
Police said Lewis was dead when they arrived around 6:30 p.m. They would not say how long she had been deceased.
An autopsy completed Thursday by Will County Coroner Patrick O'Neil revealed multiple injuries due to blunt head trauma, which authorities said was caused by an assault. The final cause of death will not be determined until toxicology reports and the police investigation are complete, officials said. Both could take several weeks.
Detectives did not find evidence of forced entry into the home, and police said they do not believe there is a threat to neighbors. Several neighbors said they called Naperville police late Wednesday and early Thursday worried for their safety.
"It is safe to say she knew her assailant," Bell said.
Bell confirmed Lewis' mother also lives in the townhouse on Worthing and there are no other current residents. The mother was not home when she called police and was concerned she couldn't reach her daughter by phone.
Bell said police have received previous calls from Lewis' mother to check on her in the past.
"We do not believe (Lewis' mother) is involved," Bell said. "She is cooperating with police, and processing and grieving the loss of her daughter."
On Thursday, two police cars were parked outside Lewis' townhouse at Worthing and Townsend Circle in the Winchester Place subdivision. The area was cordoned off with yellow tape while officers and forensic investigators worked inside the home, where the door was propped open.
A forensic detective removed eight brown, paper bags from the home around 3:15 p.m., but Bell said police do not have a murder weapon.
He said police are following several strong leads.
Several neighbors, who all declined to provide their names, said they knew little about Lewis and only waved to her when taking out garbage. She primarily focused on caring for her mother, they said.
Police said they are unsure if Lewis was employed.
Funeral arrangements are pending, but will be coordinated by Friedrich-Jones Funeral Home in downtown Naperville.
Anyone with information is asked to call Naperville police at (630) 420-6147.
• Daily Herald staff writers Marco Santana and Megan Bannister contributed to this report.