RIVERSIDE, Calif. (AP) — Authorities say a convicted serial killer whose victims included two young boys has died at a hospital in Indiana. Joseph Edward Duncan was on federal death row. The 58-year-old had been diagnosed with terminal brain cancer. He was sentenced to death in 2008 following his conviction for the killing of 9-year-old Dylan Groene and three adults in Idaho. Following that conviction, Duncan was extradited to Southern California to be tried for the death of 10-year-old Anthony Martinez of Riverside County in 1997. Duncan pleaded guilty and received a sentence of life in prison.