Disturbing Bluejay (1 Viewer)

I just winessed an interesting, yet disturbing, behavior by a bluejay. I heard a skirmish in the tree above and down falls a bluejay with a house sparrow in its beak. I'm asuming very young house sparrow since there is a nest in the neighbors eave and 5 other sparrows were diving & hitting the bluejay, while it repeatedly pecked at the little screaming bird. It then flew into the tree with the bird still in it's beak and proceeded pecking at it until the little bird's head came off and the blue jay flew off with the house sparrow's head. And also intersesting was the male cardinal that came down with them and sat about a foot away and watched.
Is this normal bluejay behavior or do I have a disturbed bird?

Blue Jays are known to be nest robbers. Although, I can see how this experience would be a bit disturbing, whether it was normal behavior or not.

The bird had already fledged, the bluejay attacked it while it was in a tree in our backyard. It was weird.