Two radar blips with no transponder information, one is P3 and other is cargo door. All four accidents had bomb as first explanation. Explosive decompression is an aviation term used to mean a sudden and rapid loss of cabin pressurization. A loud noise is associated with this event but not necessarily an explosion. The severity of an event occurring is independent of whether that event occurs.
Trivial events have severe consequences on the sea and in the air.
Another accident with the same similarities except for a torn off nose and less wreckage may also be included in that class. The unifying cause for all four accidents is the inadvertent opening of the forward cargo door inflight.