I'm a historian of science working on a journal article/ possibly a magazine article on the topic. There's a ton of misinformation, but one place to start that's really fun to browse and, presumably, a legit source of documents is the CIA's own recent FOIA release from last year, about their "Animal Partners" program:

https://www.cia.gov/library/readingroom/collection/animal-pa...

By the way, on the off chance that anyone reading this was involved in or has a friend or family member involved in this kind of work, please let me know if you think they might want to talk to me! I'm currently interviewing people. Contact info in my profile.