Dennis Lynn Rader (born March 9, 1945 ) is an American serial killer. He murdered 10 people near Wichita, Kansas between 1974 and 1991. He was known as the BTK killer (or the BTK strangler). "BTK" stands for Bind, Torture, Kill. He was named this because that was what he did to the people he killed. Letters were written soon after the killings and sent to police and to local news outlets. They talked about the crimes. The letters had information which only the killer and police knew about the crimes. The letters stopped being sent for a long time. In 2004, they started being sent again. This led to him being located in 2005 and found guilty of the murders. Rader was sentenced to at least 175 years imprisonment.