The local Patch news service sends e-mails here from time to time, usually of little import, but these two recent messages are very much of significance. Even if their links expire by the time you see this, please read the words of the links themselves.
https://patch.com/new-york/merrick/envelopes-stolen-merrick-post-office-drop-box-police
https://patch.com/new-york/merrick/4th-person-arrested-stealing-merrick-post-office-report?utm_source=alert-breakingnews&utm_medium=email&utm_campaign=alert
The named post office is the one I've been using. I walked past it just after the first message came and I noticed that the drop boxes outside the building were the same ones that have been there for quite some while. (One gets to notice all the little nicks and dings in the paint.)
Now look at this excerpt taken from the first URL above:
The drop boxes showed no signs of physical damage, no signs of having ever been forced open.
If a drop box was "opened" without sustaining any visible damage, that means that the drop box was opened using a key which could only have been provided by a post office employee. Think of the term "inside job".
The lesson I personally draw from this is to NEVER post any mail using any drop box. I will ONLY deposit outgoing mail into the deposit slot inside of a post office building. One can never be totally sure that something bad won't happen anyway, but I figure that the chances of mail theft are at least diminished.