I don't think that there is any question that assassinations, scientific or otherwise, have been and are "part of the CIA's record". But Madsen's contribution to this issue is his review of the research into bio-weapons conducted by US agencies, and his survey of many nations' leaders who have opposed the Empire's policies and actions and their subsequent deaths due to cancer.
Chavez said the probability of so many Latin American leaders developing cancer at the same time was "difficult to explain".Of course, we shouldn't forget one of our own labor activists, Karen Silkwood, who was contaminated with plutonium back in the early 1970s by Kerr-McKee corporate agents because she complained too vigorously about nuclear health and safety issues at the plant. Apparently they were in a hurry to shut her up because before she got cancer, she was killed in a mysterious auto accident.