For more than 30 years, the case of the BTK killer was one of the biggest unsolved mysteries in America. The BTK killer killed 10 people in and around Wichita, Kansas, between 1974 and 1991.

Dennis Rader first committed murder in January 1975 when he killed four members of a family. For the next 15 years, he killed six more victims, all females. During his murder spree, Rader taunted police by sending them bizarre notes. In the first note he sent, which was found stuck in a book in the Wichita Public Library, Rader admitted to killing the family and provided details that only the police knew. He also created a nickname for himself – BTK (Bind, Torture, Kill). Rader sent several notes to the police, either directly or through the media, and some notes contained poems, puzzles, and pictures.

The local police and FBI spent thousands of hours analyzing the notes, following up on leads, and interviewing suspects. However, they were never able to tie the murder to Dennis Rader.

In 2004, after more than 10 years of silence from Rader, he started sending communications to the police. One such communication turned out to be the break in the case. Rader sent police a document created in Microsoft Office on a floppy disk. The floppy disk was immediately handed over to computer forensic experts for analysis. The forensic experts used EnCase software to examine the floppy disk and found another Microsoft Word document that was deleted on the floppy disk. The forensic experts recovered the document and after analyzing the metadata (data about data) found that it had last been modified by someone named “Dennis” at Christ Lutheran Church. Forensic experts then searched the church’s website and found that Dennis Rader functioned as president of the church’s congregation council. After police and FBI personnel checked Rader’s background and examined DNA evidence, they were able to link him to the BTK murders.

Dennis Rader originally pleaded not guilty, but later confessed and provided police with hours of details surrounding the murders. Dennis Rader currently resides in Kansas’s El Dorado Correctional Facility. His earliest possible release date is February 26, 2180.