For those asking why the UN is saying "maybe", it's because the High Commissioner for Human Rights is not allowed to make the legal determination about whether

For those asking why the UN is saying "maybe", it's because the High Commissioner for Human Rights is not allowed to make the legal determination about whether a country or any entities have committed a crime against humanity. Only the UNSC & UNGA (and subsidiary bodies) or international courts like the ICC or a specialist International Tribunal can make that determination. The High Commissioner's role is to perform an investigation and alert the UNSC, UNGA, and UNHRC to potential crimes while also gathering evidence. It's then up to those bodies, which are run by their member countries, to take it further.