I would look around, search the area for a while silently, then signal with whistle, mark the location in map etc., tell about it authorities later, but probably never touch the backpack thinking it might be some kind of trap. You never know.



I agree that Blast's suggestion is very good. But as far as not touching the backpack he wrote: "4. Take a picture of or write down the ID information." How do you find out ID information without touching/opening the backpack?