One of the open questions from the Mavi Marmara incident was whether we would definitively say that the IHH militants had their own live weapons. Certainly the soldiers who were on the ship said, at the time, that they were being fired upon with live weapons, and we had already heard that there were bullet casings on board that did not match any IDF-issued weapons.
The JPost mentions today that "forensics experts were currently examining the origins of bullet casings found on the Mavi Marmara that did not come from any of the IDF-issued weapons used by the naval commandos."
However, before any definitive accusations are made, the IDF is still checking to ensure that none of the soldiers on board had brought with them any non-IDF weapons that could account for the casings, according to a Hebrew YNet article.
(h/t Islamo-Nazism blog)