Because in those times, African Americans were rarely believed in court and he was afraid that even if he told to truth, he would be found guilty.
He postulated in a book that it would be better to release true witches than to punish innocent people.
To be non-biased, have thorough research habits, a good work ethic, to produce the story as closely to the true events as possible (no filler or otherwise distracting language to take attention away from the topic)
