Everyone colluded with whoever committed the crime either through silence or through denial.
To avoid embarrassment, Israel was accused because it is the usual suspect and it’s easy to accuse it of killing heroes, good men, and even evil men. In Arab media, Israel was accused because it killed Ghassan Kanfani and Kamal Nasser before. However, evidence which surfaced during the trial of suspects involved in Naji’s assassination suggested otherwise. It turned out that there were Israeli spies who had known about the weapon and about one of the suspects and that they were tracking him down in case the target was Israeli. It seems the Israelis were aware of the plot but they let the criminal kill Naji. They did not order the hit and it did not harm them – or at least this is what the investigation showed at the time.