If they found speartips with the bones, that would mean one of them dropped and died by a bunch of spears, together with the bones of a large animal. That would suggest the person they found was preparing the animal to be roasted, and he somehow met his demise.
The setup of it smells fishy to me.
At that point in time, man was primarily a nomad. You know, hunter/gatherer - if it’s too big to lug back to the village, then you move the village to the dead elephant. Elephants would be slow moving, lots of meat, and you could basically hunt one down, build a fire, spend a couple days feasting and then move on.
Extinction seems obvious, Elephants take decades to reach sexual maturity, a group of humans who have learned how to hunt them could easily consume them into extinction. They don’t run like Deer or Elk, produce more meat - it doesn’t seem too far fetched to see these animals as an ideal food source - until they are all ate up.