Complex sentence: Reports also question whether the poison involved was actually crocodile bile; several studies have indicated that the substance is relatively harmless, and that the actual poison may have been cardiac glycosides found in local plants.
Split into simpler sentences: Reports also question whether the poison involved was actually crocodile bile; several studies have indicated that the substance is relatively harmless. The competing theory is that the actual poison may have been cardiac glycosides found in local plants.