Confusing orca photo


These two orca / killer whales passed under our boat and surfaced a few meters (yards) away. Explanation: looking at the photo their appears to be a dorsal fin at the top of the photo but it cannot be from the main orca because that would mean it was coming out of it’s belly. The belly of an orca is white and it is possible to see the tip of the tail at the end of the photo. So it could be one orca diving over the back of another or the dorsal fin could be the tail of another orca and the second one is following too close. Either way it was close.