Rescue workers say 60 pilot whales that risked becoming beached on a Scottish island may have been accompanying a sick member of their pod.
The charity British Divers Marine Life Rescue said Sunday that one of the animals had died, and the others had disappeared from view.
A post mortem indicated the dead whale may have died of an infection.
The whales arrived at Loch Carnan in Scotland's Western Isles Thursday and came close to beaching Friday morning, but were driven back into deeper water.
The rescue group's Dave Jarvis said that is appears that these "extremely social creatures" have been accompanying an ill member of their pod whose "infection may have caused this animal to strand."
He said rescuers would be alert in case the pod reappeared.