Criminal investigation of a police dept....
I'm quite open to the argument that neighbors who want the range closed are spreading lead around. Hard to see how lead fragments (not dust) could travel a fair distance (i.e., to somewhere on a school described as across a street). The rest is just the usual hysteria.
UPDATE: the comment is quite perceptive. I am president of a gun club where folks tried to drum up a hazmat issue. Bottom line: lead does not dissolve in water. Without such, it can hardly affect a human. Nor get to the water table, here several hundred feet down, thru rock. I found an account of excavation of a Roman-era lead smelter in Britain: in 1-2 millenia, its lead had migrated two or three feet downward. The other side investigated lead dust transport by wind. No, no evidence there, either. And it turned out that the ordinary soil in the area (edge of mountains) was higher in lead and arsenic than EPA standards. So they fell back on the fact that everyone inadvertently ingests a bit of dust daily, and argued some range users might (if somehow they ingested all their dust from the backstops, which had almost all of the lead) in twenty years be in some trifling danger.
Our response: there were a few retired folks who virtually lived at the range house. It was their club house, they went there seven days a week and spent most of the day there. We had a doctor run their blood levels, and they were way BELOW the national average. Doc commented that most of our lead exposure comes from ... driving a car. Roads have lead dust from decades of leaded gas. These folks were spending their day at the range, rather than driving, and so wound up with lower lead levels.