Police impound/forfeiture powers and permissions in Minnesota are constrained by state Supreme Court decision, on Fourth Amendment grounds (despite forfeiture being a civil rather than criminal matter).

This Strib link. Strib offers no links, but oral argument of the two cases is online, here (Rhode), and here (Garcia-Mendoza). Opinions are online here (Rhode), and here (Garcia-Mendoza).

Garcia-Mendoza is the forfeiture case. Rhode involved suppression of evidence in a criminal prosecution, with a Constitutionally improper auto impound/search at issue in Rhode.

An online opinion in a newly decided "stand your ground" (aka "duty to retreat") Minnesota case, here.