They look like blazing cunts,  they probably made his life hell.

well, the article refers to the mother and sister in the past tense, plus it shows a mugshot, so yeah, I'm sure he killed them. 

It's amazing how, when motivated by even a simple urge, someone can so easily destroy your life and erase you from existence. Everything you've ever lived for, gone because someone was upset at you.

This isn't that bad...it was probably just a dare or something

As disturbing as this is, it's a fascinating look at just what 911 dispatchers have to handle. I mean, jesus... o.O

It's a shame, but oh well to prison he goes.

Well, I never watched Dexter, but this boy (in the 2 minutes I listed to his call) failed to show any emotion concerning his deed or his victims. His expression was as blank as it gets. Now, I'm no psychologist, but to me it seems that he may simply not be able to feel anything about that and never has - a classic Psychopath/Sociopath.

I am wondering why it took over 20 minutes for police to show up to a shooting being reported...

Sad, but some people don't need a reason to do what they do. I am hoping that this guy is able to give back to the world, though seemingly impossible at this point.

They probably didn't feel there was an immediate threat since dispatch was keeping him talking and since he was turning himself in with no intention of hurting anyone else.  No need to cause a panic.