The parents are but one significant color in the rainbow of reasons for tragic shootings. The first reason is $. Its all about the Benjamines.
Its the manufacturer profits #1 and secondly the fun of effecting something at a distance as if a person has the psychic power of precision or revenge. Yeah - guns are fun, almost magical, for those who enjoy them. Then there is the psychological training for soldiers regarding the gun...don't get me started...

The 2nd ammendment is just a farcical legal excuse for gun makers.
The 2nd ammendment is also good for those who depend entirely on guns to feed their family but they are few. It was the NRA $ that gave immunity to the gun makers themselves and who still bear no legal respondsibility like car makers to this day.

Involuntary murder is the legal term in the Michigan charges against the parents. I prefer 'unintentional' murder since you may not intend to commit murder yourself but you help in the commission of murder. There is nothing involuntary about it. (they volunteered)

The child called his new gun 'my beauty'.
"The beauty of a gun in a small man's hands is what what makes them feel big."
quote donuel