An man convicted of murdering a woman after breaking into her apartment as she slept was put to death Thursday evening in Alabama in the nation’s fourth execution using nitrogen gas.

A “vicious” killer and rapist was executed by the state of Alabama on Thursday, becoming the fourth death row inmate in the U.S. to be die by with nitrogen hypoxia.Demetrius Terrence Frazier, 52, was convicted of the 1991 murder of 41-year-old Pauline Brown.