Dennis Rader also known as the BTK killer was one of the more infamous serial killers in our world. He sent letters describing the details of the killings to police and to local news outlets during the period of time in which the murders took place. Evidence such as these letters were major factors in proving Rader was the killer. Although most evidence did not need to be used the authorities gathered plenty of it to connect him to the murders. Because Rader did not contest his guilt, most evidence was not tested in court. However, physical and circumstantial facts that would have corroborated Rader as the BTK killer include:
* Rader's grammar and writing style match letters and poems received from BTK, though none of his communications were handwritten, but typed, stenciled, stamped with a stamp set, or computer generated.
* A pay phone that the killer used to report a murder in 1977 was located a few blocks from Rader's place of work (ADT Security) at the time.
* Rader had attended Wichita State University in the 1970s. Wichita Police Detective Arlyn G. Smith II and his partner George Scantlin traced BTK's photocopied communications to two photocopy machines, one at Wichita State University and a second at the Wichita Public Library. BTK murder victim Kathryn Bright's brother Kevin, who was shot twice by BTK, reported that the killer had asked him if he had seen him at the university. A poem in one of the killer's letters was similar to a folk song taught by a professor on that campus in that time period, though Rader himself dismissed any connection.
* Rader lived on the same street as Marine Hedge, just houses away. The BTK killer's other victims were in and around central Wichita, except for his final victim, Dolores (Dee) Davis, who lived a half mile east of Park City.