Not overworked. Wild elephant. He might have been pissed about being chased out of their fields.
I used to work with a guy from India that told me the natives are allowed to have guns but not bullets. They can requisition them from the government a couple at a time but have to justify every shot.
I'd believe that an elephant that doesn't believe humans are all powerful could be quite dangerous. Hell, dogs are.
Besides they sent all the great white hunters packing.