MOSCOW, Idaho -- One of the last survivors of the Manhattan Project has died.
Scientist Lawrence H. Johnston designed the atomic bomb's detonator and is believed to be the only eyewitness to all three 1945 atomic explosions, at White Sands, N.M., and in Japan at Hiroshima and Nagasaki.
Johnston died peacefully at home Sunday in Moscow, Idaho, where he had been a professor at the University of Idaho. He was 93.
He was a professor of physics at Idaho from 1967 to 1988.
The university announced his death.