21.   It could not be confirmed what type of lethal gas leaked.

22.   The law provides for execution by lethal gas.

23.   The potentially lethal gas was expected to be spread through the ventilation system.

24.   Three died by electrocution and one from lethal gas.

25.   Wiese said police had also found chemicals on the property that could be used to make a second lethal gas.

26.   In his novel, the lethal gas is transported in perfume bottles by women who pass through airport security without problem.

27.   A Tokyo metropolitan police official said the substance that caused the incident could be Sarin, a lethal combat gas that was first invented by the Nazis.

28.   And as for the lethal gas attacks on the Tokyo underground system, Naganuma added they were extremely rare and the culprit had already been caught.

29.   Takahashi, whose husband was a subway worker who died after inhaling the lethal gas, said she would continue attending the trial.

30.   The National Poison Centre said the lethal gas may be released in the presence of moisture, acids or even extreme heat.