My theory is that he was an senior elder of his tribe who was either challenged or challenged the leader. (evidence: the expensive furs)

He lost (contrary to the article), was expelled and was followed by some younger member or members and killed to make sure he didn't come back. (evidence - no good bow and only some headed arrows)

His belongings were left either out of respect or that the killers didn't want it known that they killed such a respected elder.