Federal agents are back at the two Iowa farms at the center of a Salmonella outbreak and massive egg recall. It's unclear whether this new investigation is the first step in a criminal probe. The FDA has jurisdiction to investigate crimes involving adulterated food, coordinating with the justice department. The FDA concluded its investigation into the conditions of the farms Monday. Eggs from the two farms have been linked to as many as 1,500 cases of salmonella poisoning.