CHICAGO (CBS) — Police are revealing more information about their investigation into the murders of an 85-year-old Sycamore woman and her 64-year-old son last August.

DeKalb County Sheriff Roger Scott said Patricia and Bob Wilson’s killer, if there was just one, is a male. Investigators have his DNA, he said, but it has not shown up on any criminal databases, so far.

“They may have not gotten in trouble before or they may have and it is just slow getting it into the system, but it eventually will get into the system we are hoping,” Scott said. “The other possibility is they may have been a juvenile.”

Sheriff Scott said the FBI’s Behavioral Analysis Unit has come up with a profile of the killer, including that he “was probably someone in a transient stage who kind of knew the [Sycamore] area but also had connections in Chicago,” because the Wilsons’ white Impala was found the next day in the Lincoln Park neighborhood of the city. It is also possible he tried to get into other homes in the Sycamore area around that time.

The FBI says it’s possible the killer needed public transportation at the time or had someone driving him around.

The profile also indicates the killer may have had clothing that may not have fit him very well, after possibly ditching blood-stained clothing from the blood splatter during the blunt force trauma killings.

The FBI believes the killer may have also appeared to have just been in a fight the night of Aug. 14 or the morning of Aug. 15 and may have paid abnormal attention to news coverage of the crime.

Patricia A. Wilson, 85, and her son, Robert J. Wilson, 64, were found dead inside her Sycamore home on Aug. 14. Autopsies revealed both had suffered blunt force trauma. Neighbors said she lived by herself, but her son would come by to help her and check up on her.

Police believe someone broke into their home, killed the mother and son, and then stole their car to flee the scene.

The white, 2010 four-door Chevrolet Impala was found Aug. 25 near the Lincoln Park Zoo. Police said it was unoccupied, and might have been there several days. Investigators found “items of potential evidence” in the car and sent them to the Illinois State Police Crime Lab.

Sycamore Double Homicide reward fyler (Credit: DeKalb County Sheriff’s Office)

A reward offered by the DeKalb County Crime Stoppers has been doubled to $50,000 for information leading to the arrest and conviction of the killer or killers.

“Hopefully people will come forward just out of compassion, but whatever it takes to bring it forward with the vital information that is what we need. So, whether it’s money or compassion, doesn’t really matter at this point. We just need to solve this case,” Sheriff Scott said.

Anyone with information on the murders should call the DeKalb County Sheriff’s office at 815-895-2155, or can call or email the DeKalb County Crime Stoppers at 815-895-3272 or Callers to Crime Stoppers can remain anonymous.