21.   Investigators have speculated that the crash was the result of a deliberate action by the co-pilot, Capt. Gameel El-Batouty.

22.   Investigators speculated that the strontium was stolen from a military facility.

23.   Investigators speculate that the cabin suddenly lost pressure causing all aboard to lose consciousness.

24.   Investigators have all along speculated that the part came from another airplane.

25.   Investigators have speculated the killing was linked to illegal business deals among Georgian criminal gangs.

26.   Investigators speculated that the sophisticated weaponry was acquired for eventual use against anti-Mafia prosecutors, who travel in helicopters or armored cars.

27.   Mafia feuds may have claimed other victims, investigators speculate.

28.   Other investigators speculated that smaller amounts of pollution accumulated over several years to the point where they wiped out the reefs.

29.   Some investigators have speculated he crashed the plane deliberately.

30.   Some investigators have speculated that the streaks might have been caused by burning debris from the plane itself.