German doctors identify gas used in Russian hostage rescue

German doctors say they've identified the mysterious gas Russian authorities used to bring an end to a hostage drama in a theatre in Moscow.

The doctors believe the gas is Fentanyl, a chemical in the same family as morphine and heroin. It can abruptly paralyze the respiratory system.

• FROM OCT. 27, 2002: Gas blamed for killing 116 hostages

The bodies of two German nationals were flown back to Germany after the hostage taking ended.

• INDEPTH: Russian knock-out gas

Moscow's chief public health officer said Sunday 116 people died from the gas used by the Russian military.

Chechen rebels held hundreds of people hostage while demanding an end to the war in Chechnya.

• FROM OCT 28, 2002: Putin threatens to strike at terrorists 'wherever they may be'

Despite international speculation, Russia's military still won't confirm the identity of the gas. They maintain it must remain a military secret to prevent future terrorists from arming themselves against the gas.