I can be sympathetic to the libertarian view that you should be able to sell whatever you want to whoever consents to buy it, but once you talk about killing people who cause you problems, you're not the hero any more...
I am hesitant to believe those details of the case. First, because so much malfeasance went on with multiple investigators on the case. Second, because it was awfully close to entrapment, and lastly, because none of those details were brought up in the case that put him away for multiple life sentences. I am skeptical they would leave those details out if they were unimpeachable.
I can be sympathetic to the libertarian view that you should be able to sell whatever you want to whoever consents to buy it, but once you talk about killing people who cause you problems, you're not the hero any more...