We need to stay on top of this report, and see what happens. Whether the cop gets away with it scot-free, or if, as triggerhippie suggests, he loses his job and goes to jail for child endangerment (he was obviously negligent)like the rest of us would.
Let's see if the cop made a reasonable effort to secure the weapon. Kids can be quite cunning and devious. Of course, in the end the kid still got a hold of the gun so it was obviously not secured very well.
What I find most disturbing about this story is that no one reported it. I'm presuming he showed the weapon off to a lot of people.