DTOTB double header—two mysteries

I saw two raptors ahead on the beach. They took off, and flew over me. Large, with a most unusual wing pattern: white on the inside, black on the outside. Not just the flight feathers: a clean line in the middle of the wing. Stranger still, what they dining on appears to be another of the same species. Note the beak (head is bent under).

dogs investigate dead bird on beach

I have looked through hundreds of birds online and found nothing resembling these, which I would have guessed to be eagles.

Then this:

dog with dead river dolphin
I’ve seen this DTOTB before — any idea what it is?

 Update: river dolphin.