Punks.
I’m sure drugs were behind it.
Link.
Can’t they find a way to transport food to the elephants? 
They are desperate, and driven by starvation. I think if I were starving, and saw trucks carrying food going by I’d be tempted to hold them up and gorge myself too, especially if I had offspring that were also starving.
Closing the road at night will save some of them. If you are interested, here is a link to Elephant News where I found the link.
Now with photographs and sad news.