Good post, B.A. This whole thing is chilling.
The investigative technique, or tactic, of the letter and the thinking behind it seems to be seriously flawed and looks, in my eyes, to be utterly ineffective. Eliminating wrong (guilty) suspects, making the wrong suspects (innocent) look more suspect, tipping off the perpetrators, wasting precious time and money etc etc. Does anybody have any idea of how many .40 Glocks there could be in the area? Is 60 even approximately plausible? Might there be 600? 6000? And how big is the area? How do they even know it was a Glock (can they actually determine the manufacturer from the fired slugs/casings)?