If a person finds a cell phone and the owner locks the cell phone, still has service to that phone, and is making an attempt to recover said phone, is the finder under any obligation to return that phone? If they are attempting to hide the fact that they have the phone from its owner is there any legal recourse?

I didn't know that cars could not be sold on Sunday in Michigan. I am pretty sure that there are car dealerships that are open on Sundays. Maybe they should be reported.