Instances of Abuse of Governmental Spy Power?

[snot]

I've heard of abuses re- Martin Luther King and John Lennon. I'm looking for info WITH sources/authority, esp. on-line, re- those and any others.

(And if there are sources/authority NOT online, I think us DU'er's should talk about how to GET them online!)

This is an effort to do something that might be helpful; if you appreciate it, pls k&r so it might get more input.

Many thanks!