The proofs of those crimes are provided by UN-bodies and respected international human rights organizations like Human Rights Watch, Amnesty International…who corroborated their reports with fact finding missions, thousands of double-checked witness accounts, videos, pictures, satellite pictures,…
The cited bodies and organizations are known for their seriousness and scientific approach.
Presumption of Innocence
Presumption of innocence, a general accepted rule of lawholding that a defendant is innocent until proven guilty beyond a reasonable doubt,has only validity when impartial and free investigations into the crime can be done. In general this is guaranteed in criminal investigations.
In cases of crimes against humanity, the situation is more complicated. Non-democratic regimes have many tools at their disposal to conceal, to cheat, to lie,to deny, to cast doubt… to the extent that under normal legal procedures they would always be acquitted. And we know that historically they usedthose tools abundantly to do exactly that : to conceal crimes against humanity and to escape prosecution.
As a consequence, when dealing with the Syrian genocidal massacre, as long as it is not possible to an international criminal court to execute a full, impartial and free investigation, we have to take the reports from the cited human rights organizations for granted. The presumption of innocence does not apply.