Most indications point to death by the violent impact caused by the crash of the crew compartment into the ocean at around 200g's. More than likely, as well as mercifully, they were unconscious at the time due to the disconnection of their life-support equipment. However it occurred, it was a total tragedy with all seven brave astronauts killed.
:) POOR PEOPLe BooHoooHoo oh yeh this Sucks BORINGGGGGGGGG