The incident in question happened in October, 2015, when a terrorist stabbed a passerby in Jerusalem. A police officer who arrived at the scene shot and killed the terrorist. The officer received a certificate of appreciation for his actions at the time.
The state prosecutor was asked after the incident to open an investigation into the officer on claims that the terrorist was not posing a mortal threat when he was shot, but the state prosecutor decided to close the case. An appeal was filed and the attorney-general decided, about six years after the fact, to accept the appeal and reopen the case, according to KAN news.