The Inverse Linear Relationship of the Prophets

The Lafferty brothers killed innocent people and an innocent baby, because they believed that they had received revelation from God through the Holy Ghost. How is it that you can say that you know something is true by the Holy Ghost, while at the same time recognizing the historical fact that the Lafferty's killed innocent people? And so I think that's the reason I was like Nephi, not knowing beforehand whether I should go, and I got there.