Russian sub victims suffocated

Investigators are aboard a Russian nuclear submarine that's back in port near Vladivostok after disaster struck during trials in the Sea of Japan.

 

At least 20 sailors and civilians suffocated when a lethal gas was pumped into the ship's nose after a fire extinguishing system was activated by mistake.

 

It is the worst naval accident in Russia since 118 were killed in the sinking of the Kursk eight years ago.