On Memorial Day weekend in 2011, a quiet Florence, Kentucky neighborhood became the site of one of Northern Kentucky’s most disturbing unsolved crimes.

William “Bill” Stephenson and his wife Peggy were found murdered inside their condominium on Ridge Edge Court after family members became concerned when the couple failed to appear for church services.

But what investigators discovered inside the home raised more questions than answers.

After the killings, the person responsible remained inside the residence for hours — moving furniture, manipulating items throughout the house, and staging parts of the scene in ways detectives described as deeply unusual.

Despite the brutality and the bizarre crime scene, investigators recovered something crucial: DNA.

That genetic profile was entered into the FBI’s CODIS database in  ...