In one of the the worst known incidents of mass civilian casualties reportedly caused by coalition bombings, at least 51 non-combatants were killed when aircraft struck an Islamic State local headquarters, which was also being used as a temporary prison.

Somewhere between 150 and 400 people were being held by ISIL on petty charges at the time of the 7.45pm attack at the Al Saraya site, it was reported. Multiple sources have confirmed significant civilian casualties in the event. For example news agency McClatchy “located two sources who confirmed a high civilian death toll from the strike. One witness, an activist in Al Bab, gave the death toll as 61 civilian prisoners and 13 Islamic State guards. The Syrian Network for Human Rights estimated the death toll at 80, and said 25 of those were Islamic State Guards and another 55 were either civilians or imprisoned fighters from non-Islamic State rebel groups.”

Recovering the dead and injured from the site took many days according to VDC, which also reported 60 civilians killed: “On the first day more than 20 injured civilians were taken out in addition to 7 injured members of the organisation who were the policemen in the centre. On the second day after the attack more than 13 bodies of civilians were pulled out of the rubble and 37 more bodies of civilians on the following day as well as a number of unidentified bodies. At the time of counting 10 people were still missing.”

Among those killed were men imprisoned by ISIL simply for buying cigarettes. At least four women and a number of teenagers were reportedly among the dead. News agencies and monitoring groups, which gathered biographical details of many of those killed, initially chose not to make public the names of those killed for fear of retaliation by ISIL against surviving relatives.

Between December 28th 2014 and January 10th 2015, the United States concealed the fact that it had carried out any airstrikes at Al Bab on the night in question. Only after “repeated inquiries” by McClatchy did CENTCOM spokesman Colonel Patrick Ryder finally concede that “Coalition aircraft did strike and destroy an ISIL headquarters building in Al Bab on Dec. 28.”

On April 1st 2015, CENTCOM reassessed claims that multiple civilians had been killed in the Al Bab attack, but still concluded that there was “insufficient information to determine CIVCAS.” This was partly justified by citing an Assad regime airstrike on the city 48 hours before the US attack, “which resulted in media reports of CIVCAS as well.”

This new assessment appeared to take little account of detailed investigations carried out by McClatchy, SN4HR and others.

The use of the al-Saraya building as a holding facility for locals had been widely reported long before the US airstrike. Syrian NGOs were damning of the coalition’s actions: “There is no evidence that the International Coalition exerted any effort to ensure that there were no civilians near the building nor to be certain that the building itself was not a secret detention center for ISIL, as was widely known in town,” noted VDC.

33 unidentified non-combatant males and one unidentified civilian woman (40 years old) were listed in addition to the names below.

The incident occured at 19:45:00 local time.