Dropped from hiring process with no info given

I was in the running to be a Corrections Officer for a county sheriff's office. I took the physical fitness test and interview on the same day, and got fingerprinted for the background check stuff. Today I got a letter from the sheriff's office saying that I was no longer considered for the job. The letter had the same date as my interview, and had no information about why I was dropped from the process.

I contacted the HR rep who was my point of contact, and I was told that the Sheriff's office doesn't share information with them about applicants. Is this common in the world of LE hiring?