The Egyptian military perpetrated a crime against humanity and planned the massacre in which up to 1000 unarmed demonstrators were machine gunned to death.

http://www.bbc.co.uk/news/world-middle-east-28746899

"...The killings of at least 817 people by Egyptian security forces last year probably amount to a crime against humanity, Human Rights Watch says.

A report by the US-based group says 1,000 or more people probably died in one day around Rabaa al-Adawiya mosque.

The deaths came during demonstrations broken up by Egyptian security forces.

Executive director Kenneth Roth said the deaths were "one of the world's largest killings of demonstrators in a single day in recent history".

Mr Roth and a colleague were stopped from entering Egypt on Monday.

They were due to launch the new report at a press conference in the Egyptian capital, but were deported after being held for 12 hours at Cairo International Airport.

The group's year-long investigation focused on six demonstrations in July and August 2013 that were forcefully broken up by security forces, then under the command of now-President Abdul Fattah al-Sisi.

Mr Sisi, who was then a general running Egypt's military and was elected head of state in May 2014, oversaw the ousting of President Mohammed Morsi in July 2013.

In the aftermath his armed forces launched a brutal crackdown on Muslim Brotherhood supporters..."