Dennis Lynn Rader (born 9 March 1945), better known as the BTK Killer, the BTK Strangler, or simply BTK, is an American serial killer who murdered at least ten people in Wichita and Park City, Kansas, between 1974 and 1991. Although he occasionally killed or attempted to kill men and children, Rader typically targeted women. His victims were often attacked in their homes, then bound, sometimes with objects from their homes, and either suffocated with a plastic bag or manually strangled with a ligature.
In a series of crimes that terrorized Wichita residents in the mid-to-late 1970s, Rader also initiated a series of taunting letters he sent to police and media outlets, describing his crimes in detail and referring to himself as BTK (for "bind, torture, kill"). In addition, he stole keepsakes from his female victims, including underwear, driver's licenses, and personal items. In 1979, BTK suddenly went quiet, and despite an exhaustive investigation, the case grew into one of the most infamous cold cases in American history. Rader would later confess to killing three further victims between 1985 and 1991 that were not initially linked to the BTK killer, but were confirmed to be his doing through DNA and items found in his possession.
In 2004, after a thirteen-year hiatus, Rader resumed sending letters, where he hinted at committing further crimes. Based on items he turned over to law enforcement, he was identified and arrested in February 2005, pleading guilty to his crimes months later and given ten consecutive life sentences. He is currently incarcerated at the El Dorado Correctional Facility.
He was mentioned in Dexter: Resurrection as a part of Leon Prater's collection.