While the stories you present illustrate common paths guns take, the data may be skewed because most guns in these shootings are not recovered. A felon who murders a police officer with a gun from a trafficker is likely to quickly discard the weapon. But when a police officer is shot when responding to an incident of domestic violence, the gun is typically found. This may explain the surprising finding that most guns that kill police were purchased legally by the perpetrator. Perpetrators of domestic violence are less likely to have convictions that disqualify them from gun ownership.
That's a fascinating point with which I agree. Those numbers would be skewed. It reminds me of the claim that 90% OF THE GUNS TRACED in Mexico come from the States. If recovery of weapons in domestic violence cases is significantly higher than in street shootings, the numbers would be skewed.
Nevertheless, an important factor is unmentioned. In those cases in which the perpetrator himself was not the legal purchaser of the weapon used, someone else was. If the gun could be traced back, owner to owner, before long we'd arrive at a legal owner of the gun. He's the problem. That's why gun control laws are often aimed at lawful gun owners. They're the ones allowing guns to go to criminals.
What's your opinion? Please leave a comment.