If you really want to get a fascinating look at illegal CIA activities (mostly pre-1970), you need look no further than their infamous Family Jewels (24 meg pdf) memo. This document, compiled in 1973, is a huge account of multiple assassination attempts against world leaders, illegal domestic spying, mob ties, illegal break-ins and so on. It's almost 700 pages of illegal activity, most of which CIA employees have never been held accountable for.
You can read through this summary of the "Family Jewels", but I highly recommend you read the Jewels for yourself.
