Here are two more physicists who later regretted their contributions
Robert Wilson, The Conscience of a Physicist, Bulletin of the Atomic Scientists, June 1970, [a Manhattan Project division leader tells why he worked on the a-bomb and why he wishes he had quit]
http://en.wikipedia.org/wiki/Robert_R._Wilson
Rudolf Peierls, Reflections of a British Participant, Bulletin of the Atomic Scientists, Aug. 1985, [early a-bomb scientist talks about his a-bomb work and his regrets over the a-bombings]
http://en.wikipedia.org/wiki/Rudolf_Peierls