I didnt understand the ending of the first chapter?!

The dude that killed himself wasn't the one that killed he's family, One dude said "you're saying it wasn't "blah blah name"" so he killed himself for no reason. so it was a sad ending ;w;

the black haired dude was not the murderer, the chapter was started in such a way that we thought he was, i think he was destroyed because of that and killed himself