The UN Human Rights Office is set to investigate violations of international law by all parties involved in the ongoing conflict in Lebanon. This decision comes as a response to the escalating tensions and potential breaches of international law that have occurred during the war. The investigation will focus on assessing the actions of all parties, including the Tehran-backed Hezbollah militia, the Israeli military, and potentially others. The UN's move is a significant step towards holding all involved parties accountable for their actions and ensuring that international law is upheld during this complex conflict. The investigation is expected to provide valuable insights into the situation in Lebanon and potentially lead to further actions or resolutions to address the ongoing crisis.