World War II 'plague' submarine discovered at bottom of ocean

University of Hawaii researchers found a World War II-era Japanese sub designed to carry out an attack with biological weapons. DefenseTech has the story:

The submarine is from the I-400 Sensuikan Toku class of subs, the largest built before the nuclear-ballistic-missile submarines of the 1960s. They were 400 feet long and nearly 40 feet high and could carry a crew of 144. The submarines were designed to carry three "fold-up" bombers that could quickly be assembled...

An I-400 and I-401 were captured at sea a week after the Japanese surrendered in 1945. Their mission, which was never completed, reportedly was to use the aircraft to drop rats and insects infected with bubonic plague, cholera, typhus and other diseases on U.S. cities.

When the bacteriological bombs could not be prepared in time, the mission reportedly was changed to bomb the Panama Canal. Both submarines were ordered to sail to Pearl Harbor and were deliberately sunk later, partly because Russian scientists were demanding access to them.