A/HRC/42/17 Incidents Assessment Team acknowledged that the attack should not have been undertaken at the busy market, indicating a failure to take precautions in attack, it failed to consider the presence of a large number of children on the bus, alleging that it was transporting weapons and a Houthi leader. Even assuming that there was a military target, the timing, location, type of weapon used and the high number of civilian casualties, including many children, raises questions about the coalition’s respect for the principle of proportionality. 26. The Group of Experts also investigated an airstrike in Sa’dah Governorate, on 26 March 2019, which hit a shop near Al-Kitaf rural hospital at a busy time in the morning. The airstrike killed eight civilians (five boys and three men) and caused extensive damage to the hospital. 27. The Group of Experts investigated four emblematic airstrikes in Al-Hudaydah between June and October 2018. In three cases, the airstrikes hit buses carrying civilians, including displaced persons fleeing conflict-affected areas, and resulted in deaths and injuries. In one incident, two minibuses at a Houthi checkpoint were hit in close succession, killing 17 individuals, including at least one woman and one child, and injuring 34, including three boys, two girls and a woman. The coalition admitted possible “collateral damage” in this case, which remains under investigation by the Joint Incidents Assessment Team. 28. On 16 May 2019, in Sana’a, a coalition airstrike struck a four-storey residential building, killing at least five civilians (two girls, two men and one woman) and injuring at least eight (four men, two girls, one boy and one woman). The attack took place in the early morning, when most residents were asleep. According to the material received by the Group of Experts, the residents of the building were civilians, and no military targets were identified in the immediate area. 29. The Group of Experts investigated airstrikes in Hajjah Governorate conducted in the first few months of 2019. On 9 March, three consecutive airstrikes hit the home of an individual politically affiliated with Ansar Allah, then a nearby building and a farm where civilians had fled, resulting in at least 19 civilians killed (11 children and eight women). 30. The Group of Experts found reasonable grounds to believe that there may have been violations of international humanitarian law in connection with the above-mentioned airstrikes, as they raise concerns about the identification of military objectives and respect for the principles of proportionality and precautions in attack. Although the Group raised these issues with the coalition in both 2018 and 2019, it received no satisfactory response. Again, the Group has been limited to examining the results of airstrikes, as access to information on the targeting process itself has been denied. The fact that these patterns continue casts a serious doubt about whether the targeting process adopted by the coalition complied with these fundamental principles of international humanitarian law. There is a violation of international humanitarian law in relation to precautions in attack with respect to the airstrike of 9 August 2018, as acknowledged by the Joint Incidents Assessment Team. If there were breaches of the principles of distinction and proportionality in coalition airstrikes, as the Group considers highly likely, these also would amount to serious violations of international humanitarian law. This may lead to criminal responsibility for war crimes at all levels of command. Responsibility for serious violations caused by the persistent failure to correct errors in the targeting process would rest on the highest levels of command, including civilian officials. (b) Houthi shelling and snipers 31. The Group of Experts received many allegations of civilian deaths and injuries caused by the Houthis using indirect fire weapons with wide-area impact, such as rockets, mortars and artillery, that were indiscriminate or appeared to be directed at civilians and civilian objects. It also received allegations that Houthi snipers had killed civilians intentionally or through indiscriminate use of weapons in populated areas. The Group focused its investigations on a sample of emblematic patterns of conduct in Aden, Al-Hudaydah, and Ta’izz. Civilians in these areas felt the impact from Houthi shelling and small arms fire in all aspects of their daily lives. It was common for people living near frontlines to have their homes and livelihoods destroyed. Those displaced by the fighting in Al-Hudaydah were killed and injured as they fled in buses. 6