A/HRC/36/55 33. In its investigation, the Commission considered and investigated all potential scenarios, including claims put forward by Russian and Syrian officials. The Commission has not, however, found any evidence to support the claim that HTS or armed groups had a weapons depot in the area where the chemical bomb impacted. Satellite imagery shows damage to a structure at a nearby grain silo which could correlate with the area where the victims of the sarin release were found, though the silo and a nearby bakery were empty following airstrikes last year. Furthermore, the Russian Federation Ministry of Defence and the Syrian Minister of Foreign Affairs argue that the weapons depot was hit between 11.30 a.m. and 12.30, while the evidence laid out above overwhelmingly indicates that the sarin gas was released at around 6.45 a.m. 34. Though the Commission cannot discount the possibility that interviewees did not acknowledge the existence of a weapons depot out of fear of retaliation or out of loyalty to HTS or armed groups, it notes that it is extremely unlikely that an airstrike against such a depot could release sarin stored inside that structure in amounts sufficient to explain the numbers of casualties recorded. First, if there had been such a sarin weapons depot destroyed by an airstrike, the explosion would have burnt off most of the agent inside the building or forced it into the rubble where it would have been absorbed, rather than released in significant amounts into the atmosphere. Second, the facility would still be heavily contaminated today, for which no evidence exists. Third, the scenario suggested by the Russian Federation Ministry of Defence and the Syrian Minister of Foreign Affairs does not explain the timing of the appearance of victims of sarin exposure — well before the time, 11.30 a.m., that the Russian Federation Ministry of Defence and the Syrian Minister of Foreign Affairs provided for the attack. Finally, the impurities identified in the environmental samples analysed by the OPCW indicate that the released agent had not been purified. This rules out long-term storage of large amounts of sarin, which would have required agent purification. If, on the other hand, the facility had stored the precursor materials for sarin, an explosive destruction would not have released sarin into the air. Moreover, had there been sarin production going on at the time of the attack, the amount of agent would have been small and almost all of the agent would have been burnt off or ended up as local contamination though not in the atmosphere — some agent release into the atmosphere in such a scenario cannot be ruled out but it would not nearly be sufficient to explain the number of casualties. 35. In view of the above, the Commission finds that the claim that airstrikes hit a depot producing chemical munitions or that the attack was fabricated are not supported by the information gathered. On the contrary, all evidence available leads the Commission to conclude that there are reasonable grounds to believe Syrian forces dropped an aerial bomb dispersing sarin in Khan Shaykhun at around 6.45 a.m. on 4 April. The use of chemical weapons is unequivocally banned under international humanitarian law. The use of sarin in Khan Shaykhun on 4 April by Syrian forces constitutes the war crimes of using chemical weapons and indiscriminate attacks, and violation of the prohibition on the use of weapons designed to cause superfluous injury and unnecessary suffering. The manufacture, storage, and use of sarin also violates the Chemical Weapons Convention and Security Council resolution 2118 (2013). 36. As noted above, the Commission further investigated the airstrikes which impacted Khan Shaykhun after 11.30 a.m. It found that these airstrikes struck the al-Rahma medical point while it was functioning solely as a civilian healthcare facility treating victims of the chemical attack. Based on the fact that the medical point was struck with cluster incendiary munition, which only Syrian and Russian air forces use, and that Russian and Syrian officials acknowledged that after 11.30 a.m. the Syrian air force conducted airstrikes in Khan Shaykhun, the Commission finds that there are reasonable grounds to believe that either the Syrian and/or Russian forces conducted the airstrike against the al-Rahma medical point. By bombing the al-Rahma medical point, which also destroyed ambulances, Syrian and/or Russian forces committed the war crimes of deliberately attacking protected objects, and intentionally attacking medical personnel and transport. 29