Polish sentence has no pronouns. He can be looking for his child's passport in his wife's backpack for all we know. But we assume that both passport and backpack are his own.
But it was clarified that the tourist is male.
I just understand that turist find some passport in the forest and put it into backpack. Later he find a policeman who said to give that passport to him. So, the tourist is looking for that passport in the backpack, to give it to policeman.