I can't say I know all about this case but when I saw that image posted a few days ago I was very much like "Yeh she should get off".
Then I looked into it more and it gets more complicated.
1) The age of consent in Wisconsin is 16
2) She posted on backpage at 16 and he contacted her
3) Eventually she agreed to live with him and had been living with him for months
4) She stole his gun, shot him in the head twice, set the house of fire and stole his car to get away.
5) She was arrested when she was found at the home of her apparent boyfriend in Milwaukee
The argument being used is that the guy she killed was an abuser, which by all accounts dude was a nasty piece of work but this isn't as clear cut a case as is being made out not least because she burned the damn evidence that could be used in a self defence argument when she set fire to his home. She was also legal age and chose to live with him of her own free will seemingly too...... I think 2nd degree murder is likely in her case or Manslaughter on grounds of diminished mental state.