An Alabama death row inmate who raped and murdered a woman in 1991 was executed this week using nitrogen gas, making him the fourth person in the U.S. to die by the controversial method.

Alabama executed Demetrius Frazier for the 1991 murder of 41-year-old Pauline Brown two days before Thanksgiving.

Alabama has carried out the nation’s 4th nitrogen gas execution, putting a man to death for the killing of a woman who was raped and shot during an apartment break-in