Mortal Combat Kill's Seven Year Old

I don't take any death lightly, but I find this a little absurd. This article says that the 18 year old and the 17 year old sister of the victim of this crime killed the 7 year old because they were imitating "Mortal Combat"
If there is any truth to the video game part of this story, and I highly doubt that there is, then it has to be because the boy had serious mental illness. Mortal Combat isn't a realistic game, one of the guys shoots ice, several have magic. This is just lazy reporting by people who think that senseless crimes can be explained so simply.