Germanwings plane crash: The first rescuer at the scene
"After a few seconds on the ground I understood there would be no survivors."
Jean Sebastien Beaud, 31, is a rescuer and officer of the High Mountain Police based in Jausiers in the French Alps.
He and two of his colleagues were the first to arrive on the crash site of the Germanwings aircraft on Tuesday, just half an hour after the impact.
"We got the alert at 10:45 local time (09:45 GMT) on Tuesday, we grabbed our equipment and took off with the helicopter in direction of the area where we thought the Airbus went missing.
"At 11:07 we spotted the crash site." A few minutes later Jean Sebastien was winched down at the top of the crash site with another colleague and a doctor.
"What we saw there was surreal, beyond imagination. The smell of burned metal and kerosene was overwhelming.
"There was a lot of debris, we saw the first human remains and we immediately knew there was going to be no survivors."
"We found less than ten bodies entirely or partly preserved, to be honest only one body was almost intact.
"We do this job to rescue and help people but in this case we were only spectators, it was very distressing."
In the absence of any survivors the rescue operation turned into a search operation.
"We were instructed to take pictures of the scene for the report and we were also asked to find the black boxes."
On his smartphone Jean Sebastien shows me pictures of the scene as he found it, smoke coming out of the vast slopes covered with debris and burned pieces of metal.
On one video he recorded on his mobile you see a couple of unrecognisable aircraft parts still in flames. It then pans across the scene and reveals very graphic images including what look like body parts.
"We started to walk down slope the best we could as it's a dangerously steep side of the mountain. At the top of the hill we could see the largest parts of debris but down the slopes only very small pieces.
"After 30 minutes of research I found an orange piece of metal of about 1ft (30cm) at the bottom of the valley near the impact point and I immediately called on the radio to indicate that one of the black boxes had been found."
His discovery has since proved to be key to answering some of the questions surrounding the drama.
The High Mountain Police are special units of the French National Military Police. They are trained rescuers and they know the mountains well.
There are 15 squads of High Mountain Police as well as Lower Mountain Police, most them based in the Alps and the Pyrenees.
Well equipped, they have helicopters and rescuers on standby 24 hours a day, every day of the year.
Every night since the accident High Mountain Police officers have spent the night at the crash site to secure the area. Thursday night was Jean Sebastien's turn.
"It's very dark at night, we base ourselves only 100 meters away from the debris but we don't see anything.
"The atmosphere is pretty gloomy as we are on the site of the tragedy. The smell of burning and of kerosene is still strong and of course you can't help and think about the people who died there.
"We don't sleep. It's very cold up there and last night was very windy, there were four of us spending the night there.
"We light a fire and chat to each other to stay awake, we talked about what we saw - it's a form of therapy. Even if we don't consciously feel traumatised by what we see, it's good to talk about it between us.
"It's a way to deal with the horror we witnessed."