In case it should be said, journalists without first-hand experience in direct evidence gathering tend not to be primary sources either. It may be the case that AI will have some types of relevant first-hand experience, and may count as primary sources in a number of circumstances. I can see many possible cases in the future (maybe even a decade from now) where AI can engage in a variety of thorough investigative practices. Reaching out to communicate with people, flying a drone to inspect, or perhaps executing more more complex processes may be coming. Justification or sufficient positivistic authority may come in different degrees and kinds in this cluster of practices as well.