Cian Westmoreland was 18 years old when he enlisted in the US Air Force.
Now 28, the former serviceman served with the 606 Air Control Squadron in Germany and the 73rd Expeditionary Air Control Squadron in Kandahar, Afghanistan, as an Air Force Technician.
He built the communications infrastructure for the US military's drone programme in Afghanistan, which, according to a 2015 report by The Intercept led to the deaths of hundreds of civilians.
In 2010, after four years in the military, he left the Air Force and joined other whistle-blowers speaking out about US drone policy. The group of technicians and operators wrote an open letter to US President Barack Obama.
Here, he tells his story in his own words:
My first day deployed in Kandahar was really strange. I walked from my tent to the little box that was my office and my boss was in there smiling. He turned to us and said: "We're killing bad guys now, boys."
I had this big lump in my throat and an uneasy stomach. When I read the Bible, I learned that we're not supposed to kill people, but here I was, building the infrastructure for people to do just that.
I built a data-relay system. I also did guard shift, where I saw kids begging for water and we weren't allowed to give it to them.
One day, I realised that if I didn't load the encryption each day, nothing would happen. Aircraft wouldn't be able to use this system to implement the drone programme.
They told us in the military: "No bombs without coms."
'All you hear is voices telling you what to do'
There's no physical danger from the enemy and that's what makes the job so tough.
If you're in danger, if someone is pointing a gun at you, you can justify - in your own mind - shooting someone.
But if you're sitting in Kandahar, you're confronted with a screen where you watch people day in, day out - you might even start to realise they're not bad people.
Some people start to feel a connection to the people they're pursuing and start to understand their humanity. That can be traumatising, and you have no one to talk to.
When you're in the drone programme, you're isolated - operators, analysts, leaders all work separately. All you hear is voices telling you what to do.
You're exposed to just a limited amount of the spectrum.
People like me, who speak out about the programme, feel we've been exposed to something we see as questionable. When you don't hit survival mode - that instantaneous fight or flight mode - you won't override your critical facilities, which can leave you with a huge moral dilemma and no one to talk to.
Quite a few civilians died because of what I was working on.
Whether you're a drone operator or a technician, you're still involved. When you look at the Nazi concentration camps, you had paper pushers everywhere who moved people through the lines. They didn't know what was going to happen, but, like now, there are a lot people of who are responsible for civilian deaths who are totally unaware of their role.
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Right now in the United States we have a military that is not accountable to the public. Thousands of people are in the Joint Special Operations Command, a force accountable only to the president.
The military is out of control. The compartmentalisation of knowledge means that by 2030 the majority of people hired could be technical support or maintenance. Who's responsible then?
'A schizophrenic way to live'
In the drone programme you usually do 10 to 12-hour shifts.
It's a schizophrenic way to live. You have to go home after a mission like everything is normal.
When someone plays video games for a long time they look drained and gaunt, imagine that when there's real repercussions. It has a huge impact on people mentally.
Also the public image of the programme is so awful that you have guys trying to explain to their kids that they're not monsters.
When you think about soldiers being deployed and what's involved in that, well, drone operators are redeployed on a daily basis. I'm speaking for both technicians and operators here, especially the ones that work in the US. They are in combat situations every day with limited support and work long shifts.
'I had nightmares about killing children'
It hit me when I was in Kandahar airbase, on one side you have a McDonald's and down the road there's kids begging for water.
Those people lived an austere life, and we're sitting there from the comfort of the joystick, resolved in the idea that we're killing bad guys.
Maybe they're not bad guys. Maybe we just need fewer bombs and more communication between cultures.
When I got back from deployment I had quite a number of unresolved mental issues.
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The nightmares encompassed everything I didn't understand. I had nightmares about bombing villages, about being bombed, about killing children and trying to save them.
I was emotionally detached from loved ones and had a battle with alcoholism.
And that's just one part - there's also an insidious part - the moral injury side of things, where the more you learn, the worse it gets. You're trying to figure out what you did, why you did it and what's going on in that country.
That's what brings you to a real point of hopelessness.
Obviously, the military don't like people speaking out.
When I first went public in 2015, I spoke out with two people who were featured in the movie Drone, and another guy who was speaking out for the first time. Initially our bank accounts were frozen. Our lawyers posted it on Twitter, it got retweeted a lot, and then they opened them again.
I think the military is cautious about coming after us when we're collaborating with other groups, lawyers and activists...
However, they are trying to mitigate interactions between us and people still in the programme. I'm going to assume by now that they have communicated with everyone we know and everyone in the programme, telling them not to speak to us.
Right now 12 people from the programme have been in touch and are active in speaking out about their experiences in the programme. That number could grow and that's worrying for them.
If you break the security clearance, if you speak to a journalist or an organisation or leak documents, they send you to jail for espionage. But we signed up to give back to our country and that's why we had to speak out.
Source: Al Jazeera