The Observer.

I remember I was just sitting on my sofa, just watching morning TV.

I was watching a little bit before I start work and go on my Instagram.

And I saw the clip.

And to be honest with you,

it kind of turned my stomach a little bit.

On the 19th of September, Sam Zeneffu is sitting at home getting ready for work.

She's a Greek pool and depth diver living in the UK.

I'm months into my investigation.

The Seamass World Championships have just drawn to a close in Greece.

And in the aftermath of the competition, many free divers continue to post beautiful underwater

shots, reels of their competition dives.

They're smiling and crying at the surface as they receive a white card from the judges to indicate a successful dive.

And as Sam scrolling through these reels, an image pops up that stops her dead.

I saw Petter coming up from a deep dive.

There's a lot of frothing, bloody frothing coming out of his mouth.

He is like in a very bad state after the deep dive.

He obviously hurt himself diving.

It's an extremely hard thing to watch.

The video is a compilation of clips of Petta Clover posted in collaboration with

Vitamir Marichich on Instagram and Facebook. Petar surfaces after having what looks like a deep blackout,

his eyes rolling back in his head. He's being held by Vitamir who's trying to administer oxygen,

...