Legal Question in Criminal Law in Michigan

If you were not charged, there may be no documents. You would ultimately need an attorney to force the issue if there was something and they just refuse to give it up.

Other than civil infraction tickets and some very low-level misdemeanors, the police do not charge defendants. A prosecuting attorney (or city attorney or other prosecuting official) makes charging decisions. So, to a large extent, there would not be a document at the police department saying "so-and-so was not charged". And it would also be difficult for the prosecutor to do the same unless the police had presented them with a charge request and the prosecutor declined to issue a charge. (If that happened, there'd be a paper trail and some documentation of the prosecutor's decision.)