Well, from what you have said about your location, the time of the picture, area, etc. And also Knowing what I know from the college experience, this is a good time for the 'smokers' if you get what I'm saying.

So, here is my guess considering all of the circumstances - time of year, clothes, time of picture, no flashlight, and theZiploc bag in the blue shirt guy's hand -- looks to me like some city boys grew some smoke on your hunting grounds, and you busted them!