Is This Letter About An Heroic GR Postal Employee Real?

A Reddit user posted a letter he allegedly received from the Postal Service in Grand Rapids. In it, a supervisor informs him that his package had been saved from theft by a quick thinking letter carrier.

But some folks think the letter is sketchy for a number of reasons. What do you think?

The letter, which was shared through the photo service Imgur, reads as follows:

December 31, 2015
To [redacted]:
Your letter carrier delivered your package at 11:28am on December 30. As he was finishing his loop he noticed 3 teens pick up your package and start walking down the street. He jumped into his vehicle and chased them down yelling at them. They threw your package down and took off running. Your carrier retrieved your package and brought it back to the post office. It is being re delivered to you today damaged. Sorry for the trouble this may have caused you. If you have any questions call me.
Thanks,
[redacted]
A/Supervisor, Customer Service
Grand River Carrier Annex
Grand Rapids, Mi. 49599-9998

Some on Reddit were immediately suspicious:

Am I the only one who's bothered by the quality of that letter?
"...he noticed 3 teens pick up..."
"He jumped into his vehicle and chased them down yelling at them."
"If you have questions call me."
They also didn't even capitalize the abbreviation for Michigan correctly (MI).
The letter appears to be written by a middle school student. It just begins with a blurb about "your package". There's no introduction, no official information, and no tracking number, just a poorly written story.
It also seems strange that they would release such specific details about the indecent via a letter. That is a matter for the police, who aren't even mentioned.

The letter garnered thousands of comments on Reddit, which you can read here. 

You can read the letter in its original form here.