So I mentioned in another thread that I had federal grand jury duty for six months. While it was before the wide availability of air tags, I can say that US Postal OIG special agents follow up with these kind of issues (many of the indictment request were from the USPS agents). If I were to extrapolate what I remember from over 10 years ago, I would guess that the agents probably utilize air tags in current investigations.
However, agents only pursue mail theft if they’ve been alerted to it. Most people go to their local police and mail theft is a federal crime. I seem to recall that local police in Los Angeles reached out to their federal counterparts for one specific case, but I have no idea if this is typical.
People always forget to reach out to their congressperson for help. This is what they are meant to do and they can assist constituents get help from the postal inspectors if they reported it online to the federal inspector and haven’t received any feedback. Having reached out to my local congressperson a number of times, they are quick to respond and it’s amazing how quick various agencies follow up. (I can only assume that US Reps can be a major thorn in an agency’s ass.)