The writer said the investigating department wouldn't divulge the maker of the pistol. They did exactly that in the letter. They are looking for a Glock .40 cal pistol. The rifling patterns in a barrel are generally unique to the manufacturer i.e. direction of twist, pitch of twist, number of lands/grooves and the method of rifling (button, cut, hammer forged).
It's still a major league fishing expedition. The probability of finding the pistol in this manner is not very good.
>The probability of finding the pistol in this manner is not very good.<
Now they guy freaks out and knows he has to dump the gun or at least change barrels. They should have kept it quiet IMO.