Mink are very cunning,smart and notoriously hard to trap.
Back in the 1950's I used to trap them and muskrats for their hides,and just about everything we trapped we ate.
Times were hard,and with 10 kids on a small farm hunting was a large part of your diet.
Nothing was wasted.Especially not ammo.Every shot had to count,so you learned quickly how to shoot straight.
Chances are good if you have seen mink,there are probably muskrat around too,they use the same trails and compete for the same resources.
If you haven't caught him yet, check out this link for proper traps: