The Israeli Defence Forces are again using a tactic in their attack on Gaza that they claim is aimed at saving lives—despite it having a track record of leading to the death of civilians, including women and children. So called “roof knock” strikes involve a drone firing a low- or none-explosive missile at the roof of a building that is to be destroyed. The missile is followed a short time later by a bomb that flattens the house—but exactly how long after is not known by the inhabitants.

The tactic first came to light after the 2008/9 offensive on Gaza. One of the case studies that we at Forensic Architecture produced for the UN Special Rapporteur on Counter Terrorism’s inquiry into drone strikes focused on an attack on the Salha family in Beit Lahiya on 9 January 2009. A missile was fired at the roof of the family’s home, but they did not know that this constituted a warning. After moments of terrified confusion, the family began to leave the house. However, before they could all safely leave, a bomb was dropped, and six women and children were killed.

At a time when most attacks in Gaza are on houses, the Israeli military is anxious to present themselves as trying to avoid civilian casualties. Yesterday it released a video showing a warning missile being fired at a house that it then deciding not to strike. However, in the attack on the home of Odeh Ahmad Mohammed Kaware, Defence for Children International Palestine reported that a warning missile was followed by a bomb that killed seven people, including five children. This should be taken as further confirmation that the use of this tactic should be stopped immediately.

Not only is it illegal to fire a missile at a civilian to warn them, the missiles also frequently penetrate the roofs they are intended to bounce off, further endangering civilian lives. Israeli military lawyers argue that after residents of a building have been warned, they can be considered as combatants and legitimately targeted. This is a gross misuse of international law that enables the Israeli military to justify attacks on buildings in built up areas, populated by civilians, that they would otherwise be unable to legally carry out.