There is precisely no justification for hunting a species destined for extinction. None. Period.
Remember the photo of the woman who shot a giraffe? Now we have a Minneapolis dentist participating in a hunt in which a lion was lured (by bait) off Zimbabwe's Hwange park grounds so said dentist could shoot it with a bow and arrow. And then he screwed up the shot so they tracked the lion for 40 hours and killed it and then tried to hide the GPS collar.
The guys the dentist hired are now criminals under Zimbabwe law. The dentist should be treated as a criminal as well.
It's all over social media, but here is the story from The Guardian with video clips of Cecil, the lion.