The report I saw on this said the major problem they encountered was the animals were released at night.

Coupled with the idea that it takes 3 minutes for a tranq dart to take effect, what else can you do to stop a charging tiger at night short of killing it?

If this idiot had released these animals in daylight they might have had a chance to save them. In darkness what real defense could they have had for the local people but to kill the animals?

I agree it's sad and a terrible loss of some truly magnificent animals, which is awful, but I'll always put the value of human life above that of animals