CHICAGO (CBS) — It’s been a year since the discovery of the murders of an 85-year-old Sycamore area woman and her 64-year-old son, and so far, detectives in DeKalb County are still trying to find the one clue that will solve the case.

Patricia and Robert Wilson were found dead in their home in rural Sycamore on Aug. 15, 2016.

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DeKalb County Sheriff Roger Scott said DNA of a person believed to have been involved in the killings was also found on-the-scene, but so far, that genetic information has not pointed to anyone.

Scott says the DNA “is periodically being checked about every two weeks through the system automatically.” The sheriff is hopeful that, as new names and information are plugged into the criminal database system, a suspect’s name will pop up.

He said two detectives are still on the case full-time and a $50,000 reward continues to be offered to anyone who has information that would lead to the conviction of the Wilsons’ killer or killers.

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

“It is very frustrating for us. It’s even more difficult for the family who we remain in contact with on a weekly basis,” Sheriff Scott said.

He said it’s still unclear if there was one or more people involved.

Patricia Wilson’s car was found in Lincoln Park in Chicago about a week and a half after the murders.

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Sheriff Scott said the double-murder has made people more cautious and safety-conscious. He said “the community is more alert to things of a suspicious nature.”