Dennis Lynn Rader (born March 9, 1945) is an American serial killer who murdered ten people in Sedgwick County (in and around Wichita, Kansas), between 1974 and 1991. He is known as the BTK killer (or the BTK strangler). "BTK" stands for "Bind, Torture, Kill", which was his infamous signature. He sent letters describing the details of the killings to police and local news outlets during the time period in which the murders took place.