I haven't read anything on this story this morning, but as of last night, they still had not released a motive. This entire story is really hard to fathom. A couple of thinks that really surprise me...
-It is hard to believe that 2 guys did this to their family. I could see 1 kid having mental health issues, and doing something like this, but for the brother to go along with it seems really amazing. You would think that 1 of the 2 would either realize that this would result in life in prison/death penalty, or would decide that what they were doing is too heinous to continue.
-I don't think it is that hard to believe that a kid would feel resentment/animosity toward a parent, and end up killing said parent/parents. I could even see it with an older sibling. But, killing a 5 year old sibling is hard to fathom. Especially when you consider that they left the 2 year old sibling alone. What makes a 5 year old sibling different from a 2 year old sibling when it comes to stabbing them to death?
-Stabbing someone to death is a lot different from shooting someone to death. You have to be right next to them, and they don't usually die immediately. It usually takes multiple stab wounds and you are inflicting pain with each one. I think there is a reason that mass murderers don't usually choose knives as their weapon of choice. It would seem more likely that after 1 or 2 killings, you would be so disgusted and feel so guilty about what you have done that you would stop killing.
Of course, I guess this thread shows that it is hard to know what is going through the mind of someone with a mental disorder.