Kentucky Governor Steve Beshear’s chief of staff has died. Spokeswoman Kerri Richardson says Mike Haydon passed away Sunday. The cause of death was uncertain. Haydon became Beshear's chief of staff in 2010 after Adam Edelen resigned from the position. Before that, Haydon, who was also once the mayor of Springfield, served as Beshear's legislative director. House Minority Floor Leader Jeff Hoover tells the Lexington Herald-Leader Haydon was a "very good friend" and says he will be missed.