Spokesperson Sean Parnell said that the commander-in-chief has given the green light for Nidal Malik Hasan to meet his grisly fate, nearly two decades after the devastating Fort Hood shooting. It's a controversial and uncommon method of execution in the US - and those who have watched one unfold have conflicting opinions on the humaneness of the process. 

Hasan, 56, is one of four men on the military's death row at Fort Leavenworth, Kansas - and Parnell said 'judgement day has finally come' for him. On Tuesday (6 October), the Pentagon spokesperson shared a social media post explaining that both Secretary of War Pete Hegseth and Trump have rubber stamped his pending execution. Hasan will meet his fate in December (Bell County Sheriff's Office via Getty Images) Hasan's scheduled death on 3 December will mark the first military execution since April 1961. He was given the ultimate punishment in August 2013 by a military jury after he was found guilty of 45 counts of premeditated murder and attempted premeditated murder. 

The former US Army psychiatrist, from Virginia, opened fire with a laser-sighted handgun at the Texas military base, Fort Hood, in November 2009. It left 13 soldiers dead and another 30 injured. Hasan was left using a wheelchair as he was partially paralysed due to a shootout with police who battled to subdue him during the mass shooting - and he is now set to soon meet a similar fate to his victims. If the military execution goes ahead, his last moments will likely be extremely unpleasant. The metal chair at the rear of the room is what death row inmates are strapped to before the firing squad begin (South Carolina Department of Corrections) The procedure is expected to be similar to those used by US states who put prisoners to death with a firing squad, such as Idaho, Mississippi, Oklahoma, South Carolina and Utah. It may be comparable to the execution of Brad Sigmon in South Carolina in March last year, which saw three officials open fire at him while aiming for a red bullseye target on his chest. 

Witnesses described how they saw the double murderer strapped to a chair, which had a basin underneath it to catch blood, before a hood was then placed over his head. A curtain that had concealed the firing squad was then opened, before shots were fired simultaneously at Sigmon. 

A reporter for the Associated Press described observing his chest rise and fall several times after the bullets penetrated his body. It took three minutes for him to die after the first shot was fired. 

How death by firing squad unfolded for Sigmon Brad Sigmon was pronounced dead three minutes after his execution began (South Carolina Department of Corrections) Brutally, the bullets that were used are designed to break apart on impact and inflict maximum damage on the condemned inmate. Those who observe such executions are often given ear plugs to protect their ears. As detailed by FOX Carolina News in wake of Sigmon's death, he was strapped down to a metal chair that is bolted to the floor in the execution chamber at the Broad River Correctional Institution in South Carolina. 

Those responsible for putting him to death were Department of Corrections employees who, interestingly, had volunteered for the macabre job. The publication reported that there was a 'portal' in the wall of the execution chamber, which is where rifles that were each loaded with live ammunition were positioned, before the triggers were pulled from around 15ft (4.6m) away. 

After the warden recited the execution order, bullets rained down on Sigmon, before a doctor pronounced him dead minutes later. Although his method is perhaps more definitive that other methods such as the lethal injection, as demonstrated during Christa Pike's botched execution last week, it apparently isn't any easier to watch. 

What witnesses have described 

Reporters who saw Ronnie Lee Gardner be put to death by a firing squad in Utah in June 2010 gave chilling accounts of what happened in the moments after the trigger was pulled. The killer explicitly wished to meet his fate this way and famously told the Deseret News in 1996: "I like the firing squad. It's so much easier... and there's no mistakes."

Ronnie Lee Gardner requested a firing squad (Utah Department of Corrections) He was pronounced dead approximately two minutes after a five-man firing squad unloaded at him from 25 feet (8m) away. KSL5TV former reporter Sandra Yi explained that Gardner's head was 'restrained' by officials during his execution, ensuring he could not budge. 

"There was a strap across his forehead, so he couldn't move his head," she told Associated Press at the time. "But I could see him moving his eyes...and it looked almost like he could see us through the window, even though he couldn't. When he was shot, some of us I think weren't sure if he had passed away because we could see movement. 

"He had his fist clenched and we can see his elbow move up and down and his thumb and forefingers moving, rubbing against each other."

A chair used for firing squad executions in Utah (Utah State Department of Corrections) Others shared similar accounts, such as Pat Reavy from Deseret News, who recalled how Gardner 'kept moving' after the round of shots were fired at him. The general consensus was that the firing squad got the job done efficiently, as KTVX-TV reporter Marcos Ortiz said: "What caught my attention was that it was so sudden, so quick. Boom, boom! Just like that." 

Sheryl Worsley, reporting for KSL NewsRadio, concurred and described it as being 'over pretty quickly'. "It was cleaner than I expected and it was fast," she said. "But he moved, he moved a little bit. And to some degree that bothers me and to some degree that mirrors the last few weeks of his life...because he was fighting to stay alive the last few weeks of his life, legally, and that seemed to carry on the last 60 to 120 seconds." 

In response to the news of Hasan's execution date being set, Death Penalty Action - an organisation which opposes capital punishment - said: "There ​is nothing Donald Trump loves more than the power to kill."