The Egyptian, Ahmed Assem, who 'filmed his own death' by a sniper

The 26-year-old was one of at least 51 people killed when security forces opened fire on supporters of the Muslim Brotherhood and ousted president Mohamed Morsi.

The video shows Assem filming a sniper, who then turns to point his rifle at the camera which in turn goes black.

Assem's friends and relatives told The Telegraph that he managed to capture his own death on film with a bloodied camera and mobile phone all that was left behind.

'At around 6am, a man came into the media centre with a camera covered in blood and told us that one of our colleagues had been injured,' said Ahmed Abu Zeid, the culture editor of Mr Assem's newspaper.

'Around an hour later, I received news that Ahmed had been shot by a sniper in the forehead while filming or taking pictures on top of the buildings around the incident.

'Ahmed's camera was the only one which filmed the entire incident from the first moment,' he said.

'He had started filming from the beginning of the prayers so he captured the very beginnings and in the video, you can see tens of victims. Ahmed's camera will remain a piece of evidence in the violations that have been committed.'

Critics of the army say Assem has left a testimony of how events actually unfolded.

Mr Morsi's supporters say they were fired on from behind without provocation while they were praying.

The army rejects that, saying protesters attempted to storm the Republican Guard facility.