[sudosysgen]

What exactly do you want evidence of? That U.S. intelligence agencies disappear people? That they do so to send a message? Or are you asking for specific examples of that happening to foreign intelligence operatives? Because you will never be able to read of an example of that happening - when we learn about people kidnapped by U.S. intelligence agencies, it's only because they were eventually released. It's an inference from the fact that US intelligence agencies kill many people for multiple reasons including sending a message, and that U.S. intelligence has clandestine facilities on American soil where they commit crimes on foreign intelligence operative (See the case of Yuri Noseko) without consequence, which have only been expanded since then - the CIA now has extraterritorial black sites, so nowadays Yuri would simply have been sent to Romania and then no record would be available of his torture unless he was released.

[samhw]

That's a long paragraph, but, as far as I can tell, doesn't contain a shred of the evidence or sources I asked for?

The one concrete detail you mention is 'Yuri Noseko' [Nosenko], who seemingly was a defector imprisoned for three years on suspicion of being a spy and then released. I'm not sure how this substantiates any of your claims. It appears to do the opposite.