But, in fairness, and not to denigrate at all your friend's distressing losses and animal's injuries, these birds are wild predators. What are the officials (I assume from the Scottish Government?) supposed to do? These birds are here, they have a right to be here and that means they have to eat.
Yes, they are deadly, as are ravens, golden eagles, sparrowhawks etc. And foxes, badgers, rats, etc.
It's distressing and unpleasant and for the poor animals, traumatic and painful. But, I would respectfully argue: it's nature.