A death row inmate who killed four Oregon women in the early 1990s has died of natural causes.

A Department of Corrections spokeswoman says 49-year-old Cesar Barone died Thursday after having been in the infirmary at the Oregon State Penitentiary in Salem for several weeks.

Barone had been awaiting execution since 1995 for the murder of Martha Bryant, a nurse-midwife who was sexually assaulted and shot to death after her car was run off the road near Hillsboro.

He received the death penalty twice more, for the slayings of Chantee Woodman in 1992 and Margaret Schmidt in 1991.

Barone also got an 89-year sentence for the death of Betty Williams, who died of a heart attack as Barone began sexually assaulting her at her Portland-area apartment in 1993.