Why is Israel, and the US, so afraid of an international investigation into the Gaza flotilla killings?

don;t take this the wrong way but Israel has some blame here and we can get caught up in an international bomb fest starring Israelis, Turks and Palestinians. Though I highly doubt Turkey as a whole will cross that line. Regardless, other Arab nations could get involved, have the benefit of the doubt or prove that israel was totally at fault (we do not know all the details so do not jump to conclusions) then the sh!t hits the fan and we have to give them guns and hell, here's the "Six Day War" all over again and guess what, we're taking a stance now, this ain;t 1967.