It seems like they did the same exact shit to King, that they did to John Lennon. Except they were more aggressive and harbored a seemingly personal hatred for King whereas with most it's "just business". Maybe they felt they could get away with more because of his skin color, and the time period.

If anyone thinks I'm exaggerating the comparison, both Lennon and King had very similar messages, goals for humanity, and were harassed by the government, had files kept on them (They even went as far as to analyze and archive Lennon's lyrics, and try to ban him from the United States), and in the end, they were both "murdered" by a radical/fanatic too.