Bounties can be placed by consuming a Trace of Evil.
Bounty Hunting is a specialized aspect of PvP within the Tree of Life world.
A Trace of Evil can be consumed in order to activate a bounty debuff against the offending crminal listed on the Trace of Evil. Once a bounty is activated, the target may be killed without consequence. The bounty will be dropped when the target is struck with a last hit by a human player.
TODO: It seems to mine a bit short as description.. serves more depth in the topic.
For what I have understand.. the bounty target is tracked and showed also on the map (but here maybe Im wrong).