The official line was that Salvador Allende took his own life on Sept 11 1973, as Pinochet's fascist soldiers stormed the presidential palace during US backed coup in Chile. Perhaps the exhuming of Allende's body will reveal more information, but I suspect not.
But let there be no doubt about it - Allende was murdered by a US foreign policy that could not stand the threat of another successful socialist state in South America. The US were deeply involved in supporting the military coup, and the subsequent detention, torture and murder of thousands of Allende supporters.
We must not hold onto the idea that this could not happen again, South America's history is sadly full of such events. The US certainly was involved in the unsuccessful coup against Chavez in 2002, and in 2009 stood idly by as a coup deposed the elected left wing leader of Honduras.
May God let Allende rest in peace, and disturb the skeletons of US imperialism in South America