Alabama became the first state to carry out executions with nitrogen gas when three inmates were put to death using the method last year.

Demetrius Terrence Frazier is set to be executed with nitrogen gas for the rape and murder of 41-year-old Pauline Brown in Birmingham, Alabama.

A federal judge on Friday refused to stop what would be the fourth nitrogen gas execution in the U.S., saying the inmate had not proven his claims that the new method is unconstitutionally cruel and causes psychological terror.

A serial rapist and murderer is to be put to death by nitrogen gas in Alabama, the fourth use of the controversial execution method in the southern state.

A serial rapist and murderer is to be put to death by nitrogen gas in Alabama on Thursday, the fourth use of the controversial execution method in the southern US state. Alabama carried out three executions by nitrogen asphyxiation last year and is the only US state currently using the method.