Retired Wichita police Lt. Ken Landwehr has died at the age of 59.
Landwehr supervised more than 600 homicide investigations during his career.
Police Chief Norman Williams says Landwehr had kidney cancer and died Monday in his home.
Landwehr retired in 2012 after a 35-year career with the Wichita Police Department.
He is credited with breaking the BTK serial killer case.
The suspect, Dennis Rader pleaded guilty to killing 10 people in the Wichita area between 1974 and 1991.
Landwehr also led investigations that led to arrests in two quadruple homicides within a week of each other in 2000.