Zane Michael Floyd’s lawyers said he does not want to die, but that the rare firing squad method would be more appropriate should it come to that.

‘This is not a delaying tactic’, Brad Levenson, a federal public defender representing Floyd, said on Monday.

‘Execution by firing squad… causes a faster and less painful death than lethal injection’, Floyd’s lawyers wrote in a court filing on Friday.

Levenson said that gunshots to the brain stem are ‘the most humane way’ to carry out an execution. Floyd’s attorneys say that Nevada’s three-drug injection would be cruel and unusual punishment, as well as violate his constitutional rights.

The three drugs used in the process are the painkiller fentanyl; a sedative, diazepam; and a paralytic, cisatracurium. Nevada no longer allows firing squads for capital punishment sentences. The state law calls for lethal injection.

Challenging the execution protocol requires the defense team offer an alternate method of execution.

Floyd, 35, was convicted in 2000 of fatally shooting four people and seriously injuring a fifth victim at a supermarket in Las Vegas, Nevada, in 1999.

His lawyers have asked a Las Vegas federal judge to stop his execution, possibly in June, until prison officials ‘devise a new procedure or procedures to carry out a lawful’ means of putting him to death.

Floyd would be the first person to be executed in Nevada in 15 years. In 2006, Daryl Mack asked to be executed after he was convicted of raping and murdering a woman in Reno in 1988.

Mississippi, Oklahoma and Utah are the only three US states that permit a firing squad for capital punishment.

An execution by gunfire was last done in Utah in 2010.