Evidence leading to the BTK murderer arrest

On February 25, 2005 Rader was stopped by authorities while in route to his home. At that point several law enforcement agencies converged on Rader's home and began searching for evidence to link Rader to the BTK murders. They also searched the church he belonged to and his office at City Hall. Computers were removed at both his office and his home along with a pair of black pantyhose and a cylindrical container.

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:
DNA analysis of BTK's semen and material taken from underneath the fingernails of victim Vicki Wegerle match the DNA profile of Dennis Rader.
Rader's grammar and writing style matches 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 ADT Security (Rader's workplace 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 copier 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.
Two of the victims (Julie Otero and Kathryn Bright) worked at the Coleman Company, though not during the same period that Rader worked there. Rader worked at Coleman only a short time and not at the same location as the victims.
Rader's 16 plus hour confession, given fully and freely after receiving multiple Miranda warnings and recorded on over 20 DVDs, in which he alluded to all 10 known murders in remarkable (and grisly) detail.
Semen found on Josephine Otero or near the bodies of his victims Josephine Otero, Shirley Vian and Nancy Fox was critical evidence linking Rader to the crimes, and DNA obtained from fingernail scrapings of Vicki Wegerle's left hand matched Rader's DNA, eliminating any doubt that he was her murderer. Rader also sent trophies to police in his letters, and others were discovered in his office. Other cold cases in Kansas were reopened to see if Rader's DNA matched crime scenes, but Rader's confession was limited to the 10 known victims and police and prosecutors do not believe there were any more victims because of the extensive records and memorabilia he kept on each of his victims.