Teenager kills 4-year old sister

I just wanna make a statement that I have no clue what’s goin on with the teen. I’ve never been in that position and all I’m givin is deranged opinion. NOW, what the fuck thought process suggests that killin a 4 year old is the only solution? If he was like 9, 10 then maybe I could understand the child not really knowin who to turn to (if the molester is a family member or has threaten him). But the kid was 18. Legally he coulda ran away. He coulda called the police. He could’ve done a lot of things besides kill the baby. That’s just fuckin ridiculous. There is really no excuse for that. And then he admitted it. Does he hope stayin in prison will protect him from the molester? Does he plan on givin up the molester’s name durin the trial? Does he not know that they rape people in prison? ESPECIALLY those who commit crimes against women and children? That’s why Chris Brown didn’t wanna go to jail…he’s too pretty and woulda been Christina Brown within minutes. Sick world we live in.