Before coming to the US, my dad was involved in some interesting stuff. When I was a kid, someone from that life tried to contact him. He called the FBI or CIA (I am not sure which) and the government tapped our phone line. The person calling heard the click, said something like "now why did you have to do that" and never called again. I would hope in the 40 years since they have figured out how to hide that click.

On a side note, when his mother died he tried to renew his visa and found out all the information about him was being sealed by the CIA. Later found out the love of his life that he left behind was working for the CIA. I am hoping at some point in my life I can get those files released and see what was really going on.