There is no such thing as karma.
Oh, no, there is karma, but not the mystical sort of nonsense that Religionists intend, but there is this effect of how you live your life filling your social circle with either good or bad values and vibes. IF you live righteously and honorably, the evil little lying shit4brains tend to avoid you and thus you are not impacted so directly and with the full throated evil as those who are inclined to gossip, slander and betray good or innocent people. Thus your life is improved by not being an evil little shit.
The same is true if you live a life of horrible behavior, slandering people without cause, lying about everything, engaging in theft and other sleazeball tactics. IT comes back to you because that is what you are filling your world with and what you acclimate to.
Birds of a feather tend to do to each other as they wind up getting done to themselves.
There is only the Word of God and the judgments of God as it is written:
Be not deceived; God is not mocked: for whatsoever a man soweth, that shall he also reap.
Galatians 6:7
We do not know the intimate details of this mans life nor do we know if he was perhaps working as an informant as Jim suggested. I had never heard of the man before reading the news story and posting it. For all we know - if he was leading a rebellion against authority and trying to incite violence - he could have repented and become a follower of Jesus Christ. It is something to consider before rushing to judgment.
And yes, while God and you may forgive them, they do not escape the justice of the law, in theory.