The second should read "Does the victim have to identify his assailant?" They're both correct because they're asking two different things. The first asks if it's something the victim should do. The second is asking if it's something he must do. Which one to use would depend on what kind of information the person asking the question is looking for.

You're misusing the word 'variant'

I think no. Because if it is a victim, any reason isn't able to change this reality. It have to get used to death.