We actually had a case like this on IotD before. This wild elephant was believed to have killed Bangladeshi villagers in the Bero junles near the Jharkhand state capital Ranchi. He was captured and killed by forest officials.
I guess they feel that if an elephant kills he's more likely to kill again; or they have some sort of tribalish attitude towards these things.
But the tying-up part is really too much. Seems almost like they felt there had to be a kind of payback involved. They had to kill him "execution style".
(Ed. note: I didn't really mean to skip the holiday. I'm just lazy.)