Enormous bird eating a dove in back yard

I could not get clear images, and I can't tell what sort of hawk this is. It had bands on its tail, no reddish color that I could see, white spots on its back which is unlike any hawk picture in my bird guide. I vote for northern harrier. But I really do not know.

The ominous thing is that the little dog next door disappeared last night. I see that the great horned owl could possibly be a culprit in that sad story. We still hope the dog will turn up.