I'm thinking we need a bit of backing up for this rather bald statement. In understand that Pierre Salinger and others have fingered the U.S. Navy, but their arguments seem very fringe-ey to me. A bit more explanation that just this one sentence seems in order.
No more fringe-ey than the idea of a terrorist missile. In my opinion a navy accident is many times more probable than a terrorist missile. The recent incident in Russia with the Israeli plane for example. There are some interesting web-sites supporting the friendly fire POV. But an on-board accident is more likely than both.