BTK stands for "Bind, Torture, Kill," which is the nickname given to a notorious serial killer named Dennis Rader. He was active in Kansas from the 1970s to the 1990s, committing a series of brutal murders. Rader taunted law enforcement and the media with letters detailing his crimes, which contributed to his infamy. Rader was finally apprehended in 2005 after a long investigation. He was sentenced to ten consecutive life terms in prison without the possibility of parole. His case has been studied extensively in criminal psychology and remains a significant example of the complexities of serial criminal behavior.