Rootclaim is a collective of specialists that use probability modelling and crowdsourced evidence to mathematically analyse competing hypotheses to reach conclusions that can better represent the best available understanding of complex politicized situations. A major area of research for Rootclaim has been the contested 2013 Syrian chemical weapons attack in Ghouta, the deadliest chemical attack in decades and a “red-line” for foreign intervention in the Syrian Civil War. But according to Rootclaim’s study, titled: “Ghouta Sarin Attack Review of Open-Source Evidence Michael Kobs, Chris Kabusk, Adam Larson and many helpful citizen investigators”, the attack was most likely carried out by insurgents not the Syrian government as commonly believed. Does a new open-source study on the Ghouta chemical attack shed new light on the Syrian Civil War?